• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권12호
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• pp.624-630
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• 2001

The trend of the regulations on environmental issues are getting tight. Responding to this trend new technologies such as moving electrodes, wide pitch and pulsed power supply are also introduced in the electrostatic precipitator(EP) systems. The introduction of wide pitch and moving electrodes enhances the system performance of the EPs by improving air-flow and by improving the ash reentrainment on rapping. The power supplies for the EPs developed up to date include thyristor-based dc or intermittent type, SMPS(switching mode power supply) type and the pulsed-power supply type. The use of the pulsed ones is known to improve dust-collecting efficiency of high resistivity ash and reduces back corona occurrence in the collecting plate. There are two kinds of pulsed-power supplies; one with pulsed transformers and the other with direct dc switching devices. The latter uses rotary spark gap switches or semiconductor switches. Both have the merits and demerits: the spark gap switches are simple and robust but has short life time, hence, high maintenance cost, whereas the semiconductor switches have long life time but are costly. In this study, A high voltage power supply with superimposing voltage pulse on dc source was developed for EPs. This study describes circuit topology, operating principle of the scheme, and analysis of experimental results on Dong-Hae Power Plant. The pulsed power supply consists of a variable dc power supply with ratings of 60kV, 800mA and pulse generator which is made of high voltage thyristor-diode switch strings, an LC resonant tank and a blocking inductor. The pulse generator generates variable pulse-voltage up to 70kV using a high frequency resonant inverter with a variable dc source. Two prototypes were built and tested on 250MW DongHae power plant to verify the possibility of the commercial use and the normal operation in the transient states.

• 한국물환경학회지
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• 제30권5호
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• pp.549-558
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• 2014

Occurrence frequency of flood and drought tends to increase in last a few decades, leading to social and economic damage since the abnormality of climate changes is one of the causes for hydrologic facilities by exceedance its designed tolerance. Soil and Water Assessment Tool (SWAT) model was used in the study to estimate temporal variance of groundwater recharge and baseflow. It was limited to consider recession curve coefficients in SWAT model calibration process, thus the recession curve coefficient was estimated by the Baseflow Filter Program (BFLOW) before SWAT model calibration. Precipitation data were estimated for 2014 to 2100 using three models which are GFDL-ESM2G, IPSL-CM5A-LR, and MIROC-ESM with Representative Concentration Pathways (RCP) scenario. SWAT model was calibrated for the Soyang watershed with NSE of 0.83, and $R^2$ of 0.89. The percentage to precipitation of groundwater recharge and baseflow were 27.6% and 17.1% respectively in 2009. Streamflow, groundwater recharge, and baseflow were estimated to be increased with the estimated precipitation data. GFDL-ESM2g model provided the most large precipitation data in the 2025s, and IPSL-CM5A-LR provided the most large precipitation data in the 2055s and 2085s. Overall, groundwater recharge and baseflow displayed similar trend to the estimated precipitation data.

• 한국가축번식학회지
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• 제10권1호
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• pp.58-65
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• 1986

The results from a survery on the reproduction of a, pp.oximately 500 dairy cows raised in four different farming areas including Cheju city, Jochun, Hallim and Sung-up are summarized as follows; 1. At the occurrence of first estrus, the average age of the heifers was 15.1 months (330 Kg/B.W.), and at first conception 18.0 months (354Kg/B.W.). There was no regional differences. 2. The average interval of the estrous cycle was 20.4 days. And the repetition of esturs after unsuccessful insemination occurred on an average of 1.6 times, especially 2.0 times in the herds of the Jochun district. 3. The ages at the first calving were similar to the data recorded for the domestic mainland's herds at 27.1 months. But some regional differences were recognized within the four districts: i.e. 28.6 (Cheju city), 27.4(Jochun), 27.1(Hallim) and 25.3 months (Sung-up). There was no significant differences in sex ratio of newborns at 50.4%(♂) and 49.6%(♀). 4. The intervals of esturs recurrence and the following conception after calving were 80.0 and 95.8 days respectively. In the followsing conception intervals after cavling, 90.6-97.4 days were average for the herds of Cheju city and Jochun districts, 62.4-69.7 days for those of Hallim and Sung-up districts. 5. The average gestation period was 279.8 days, and was almost identical in the four districts. 6. The calving intervals was 377.7 days in average, and it was shorter than the data recorded for the domestic mainland's herds. Also it was reduce gradually according to the calving frequency.

• 한국지구과학회지
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• 제24권3호
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• pp.181-189
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• 2003

이 연구는 일본 중서부 지방에서 1996년 겨울철에 발생한 뇌우의 관측 자료를 분석한 것이다. 관측기간 중 35 회의 뇌우가 발생하였으며 발생된 뇌 방전 수는 4426개였다. 관측된 뇌 방전 수를 뇌 방전 종별로 구분하여 그 발생비율을 구하였고, 뇌 방전의 종류와 기압배치와의 관계도 분석하였다. 그 결과 구름 뇌 방전의 비율은 약 78%이었으며, 양극성 낙뢰가 42.3%로 나타났다. 동계의 낙뢰활동은 미약하나 0${\sim}$5시에 가장 강하였다. 또한, 낙뢰는 북서 계절풍이 강한 경우에 활발하게 발생되고 있음을 알 수 있었다. 다중뇌와 다지점 낙뢰의 분석결과 평균 다중도는 1.4이고, 평균 다지점 낙뢰는 1.2로 나타났다.

• 약학회지
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• 제51권6호
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• pp.402-408
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• 2007

The aim of this study was to evaluate the effect of menstration among the influencing factors for the GnRH agonist (as G: depot goserelin 3.6 mg) therapy prior to the planned myomectomy for women who wanted to preserve their fertility. We reviewed total 48 patients. with the G therapy prior to the planned myomectomy from August 1st, 2005 to August 31st, 2006. The patients were classified by the G group (n=28) and the immediate surgery (as S) group (n=20). The G group (n=19) underwent the G therapy for 3 month courses, and then the efficacy was evaluated by menstruation and the myoma volumes. In the G group (n=19), therapy was effective, and the mean age was $32.4{\pm}6.5$ years. After the completion of G therapy, the mean volume of the myoma by ultrasonography was reduced to $85.2{\pm}71.2cm^3$ comparing of $430.6{\pm}248.8cm^3$ at first visit. The 11 patients had menstruation and the rest 8 patients with amenorrhea had less reduced volume of the myoma ($124.05{\pm}79.85cm^3\;v.s.\;329.41{\pm}234.0cm^3$ p<0.05). In the immediate S group, the myoma volumes by sonography was also checked for accuracy (${\alpha}=1.0$). As the result, the initial myoma volume had the positive correlations to the effectiveness with G therapy. However, the occurrence and frequency of the menstruation during the G therapy had a negative correlation. In conclusion, the use of G prior to the planned myomectomy was effective in reducing myoma volume and the menstruation.

• The Plant Pathology Journal
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• 제18권6호
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• pp.328-332
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• 2002

Wheat samples showing typical spot blotch symptoms on stems and sheaths were collected from the field after physiological maturity, and were sealed in paper bags and stored in the laboratory at room temperature to study the survival of Bipolaris sorokiniana conidia on wheat straw. The materials were observed at monthly intervals to assess the conidia viability during storage. After 4 months, the frequency of individual conidia already present on wheat straw at the time of sampling was reduced and appeared to be progressively replaced by the formation of round structures consist-ing of conidia aggregates. After 5 months, distinct, individual conidia were no longer detected, and only 'clumps of conidia' were observed. These dark black aggregates or 'clumps of conidia’measured 157-170$\mu\textrm{m}$ in diameter and were grouped into boat-shaped olivacious conidia showing thick wall and measuring 50-82$\times$20-30$\mu\textrm{m}$. The germination was unipolar and below 0.5%, suggesting the occurrence of dormancy, In contrast, individual conidium produced on wheat during the growing season were 96-130$\times$16-20$\mu\textrm{m}$, slightly curved, hyaline to light pale, and euseptate with a bipolar germination reaching 98-100%. Bipolaris sorokiniana conidia produced on PDA were 55-82$\times$20-27$\mu\textrm{m}$, tapered at both ends, dark brown to olivacious, distoseptate, showed up to 1% germination, and were predominantly unipolar. Results of the present study suggest that B. sorokiniana conidia belonged to two different physiological categories corresponding to the pathogen's infection phase and its survival, respectively. The infection phase is characterized by a high germination percentage as opposed to the survival phase harboring apparent dormancy.

• 방사선산업학회지
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• 제11권1호
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• pp.39-45
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• 2017

A cyclotron is a kind of particle accelerator that produces a beam of charged particles for the production of medical, industrial, and research radioisotopes. More than 30 cyclotrons are operated in Korea to produce $^{18}F$, an FDG synthesis at hospitals. A 30-MeV cyclotron was installed at ARTI (Advanced Radiation Technology Institute, KAERI) mainly for research regarding isotope production. In this study, we analyze and estimate the items of risk such as the problems in the main components of the cyclotron, the loss of radioactive materials, the leakage of coolant, and the malfunction of utilities, fires and earthquakes. To estimate the occurrence frequency in an accident risk assessment, five levels, i.e., Almost certain, Likely, Possible, Unlikely, and Rare, are applied. The accident consequence level is classified under four grades based on the annual permissible dose for radiation workers and the public in the nuclear safety law. The analysis of the accident effect is focused on the radioactive contamination caused by radioisotope leakage and radioactive material leakage of a ventilation filter due to a fire. To analyze the risks, Occupation Safety and Health Acts is applied. In addition, action plans against an accident were prepared after a deep discussion among relevant researchers. In this acts, we will search for hazard and introduce the risk assessment for the research 30-MeV cyclotron facilities of ARTI.

• 한국방사선학회논문지
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• 제12권7호
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• pp.887-893
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• 2018

본 연구는 병원 및 대학교 등에 설치된 X선 발생장치를 대상으로 진단용 방사선 발생장치의 품질관리 항목을 적용하여 성능 비교를 하여 주기적인 성능관리의 중요성을 인식시켜 성능유지 및 관리에 도움을 주고자 한다. 우선 재현성 및 직선성 실험결과 모든 실험조건에서 합격기준에 부합되었으며 주기적인 정도관리가 부족한 GX-650장치의 경우 재현성 평가의 백분율 오차가 높았으며 직선성 평가에서는 관전압을 100 kVp로 설정 시 0.105로 백분율 오차에서 벗어나게 측정되었다. 또한 관전압 및 관전류의 정확도 평가결과 상대적으로 X선 발생횟수가 낮은 장치에서 백분율 오차가 낮은 것을 알 수 있었다. 반가층 실험은 모든 장치에서 관전압 별 반가층 기준에 모두 포함되었다. 따라서 병원용, 실습용 구분보다는 모든 장치의 정도관리의 중요성을 인식하고 적극적으로 장치의 성능관리를 시행하여 장치를 유지 관리해야 할 것이며 특수의료장비처럼 짧은 주기의 정도관리 제도를 마련해야 할 것으로 사료된다.

• The Journal of Korean Physical Therapy
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• 제34권5호
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• pp.255-266
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• 2022

Purpose: This study sought to study the effects of cross-legged sitting posture on joint motion. It also examined the correlation between the changes in the joint range of motion, musculoskeletal symptoms, and facial asymmetry. Methods: The Acumar Digital Inclinometer (Lafayette Instrument Company, USA) was used to measure the range of motion (ROM). We measured the flexion and extension of the cervical, thoracic, and lumbar spine using a dual inclinometer, and measured the ROM of the shoulder and hip joint with a single inclinometer. The Likert scale questionnaire was used to investigate musculoskeletal symptoms and facial asymmetry. Results: The data analysis was performed using the Jamovi version 1.6.23 statistical software. After confirming the normality of the ROM with descriptive statistics, it was compared with the normal ROM through a one-sample t-test. Correlation matrix analysis was performed to confirm the association between facial asymmetry and musculoskeletal symptoms. The result of the one-sample t-test showed a significant increase in the thoracic spine extension and right and left hip external rotation (p<0.001^***), while most other joints were restricted. As per the frequency analysis, facial asymmetry was found to be 81.70%. Conclusion: The independent variable, namely cross-legged sitting posture led to an increase in ROM. The study also suggests that facial asymmetry and musculoskeletal symptoms could occur. Therefore, to prevent the increase and limitation of ROM and to prevent the occurrence of facial asymmetry and musculoskeletal symptoms, it is suggested that the usual cross-legged sitting posture should be avoided.

• 한국해안·해양공학회논문집
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• 제28권3호
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• pp.171-176
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• 2016

기온과 수온의 분포형태는 발생빈도의 양상을 결정하는 기본적이고 필수적인 정보이다. 또한 기후변화에 의한 기온과 수온의 장기변화 양상 파악에 유용하다. 기온과 수온의 전형적인 분포형태는 다수의 첨두(mode)를 가지는 형태로 일반적으로 널리 사용되는 정규분포로 표현하기에는 한계가 있다. 본 연구에서는 Gaussian 혼합함수와 Kernel 분포함수를 보다 기온과 수온의 보다 적합한 분포함수 형태로 제안한다. 제안된 분포함수를 우리나라 연안 기온과 수온자료를 이용하여 추정-평가한 결과, 관측 자료의 분포는 꼬리 영역에서 크게 차이를 보이고 있는 것으로 파악되었다. 높은 수온영역과 낮은 기온 영역에서 꼬리 영역이 길게 나타나고 있다. 또한 본 연구에서 제안한 분포함수 추정 및 비교는 기온과 수온의 상호 변동관계 및 장기적인 변동양상을 파악할 수 있다. 그러나 평균 기온 및 수온 그리고 정규분포 함수 형태로는 이러한 변화 양상의 파악은 크게 제한되고 있다.