• 대한방사선치료학회지
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• 제26권2호
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• pp.337-343
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• 2014

목 적 : 최근 시행되고 있는 가임기 여성의 유방암 토모치료 시 치료영역 외에서 발생되는 산란 및 누설에 의한 난소산란선량을 측정하여 평가하고자 한다. 대상 및 방법 : 인체모형팬텀(Aldorson Rando phantom, USA)을 대상으로 전산화단층영상 2.5 mm 획득 후, Tomotherapy Planning station(Tomotherapy, Inc, USA)을 이용하여 좌측 유방암 환자의 토모테라피 치료계획(Tomotherapy Helical & Tomotherapy Direct)을 수립하였다. 난소의 산량 선량 측정을 위한 측정 지점은 치료계획면적의 30 cm 아래 떨어진 골반의 좌우 위치로 직경 1.5 mm, 길이가 12mm인 저에너지용 보상필터가 들어있는 종류의 유리선량계 (GD-352M, ASAHI TECHNO GLASS CO, Japan)를 이용하여 각 5회씩 측정하여 평균하였으며, 선형지수-선량반응모델을 이용한 장기등가선량(organ equivalent dose: OED)으로 평가하였다. 결 과 : 토모 Helical 및 토모 Direct의 두 가지 방식으로 측정된 난소의 산란선량은 좌측 난소부위가 각각 평균 $64.94{\pm}0.84mGy$, $37.64{\pm}1.20mGy$이고, 우측 난소부위가 평균 $64.38{\pm}1.85mGy$, $32.96{\pm}1.11mGy$로 나타났다. 이는 토모치료 시 비교적 모니터 단위(MU)가 크고 조사 시간이 긴 토모Helical 방식이 토모Direct에 비하여 측정된 산란선량의 양이 보다 약 1.8배 높은 경향을 보였다. 결 론 : 가임기 여성의 유방암 토모테라피 시 발생하는 좌우측 난소의 산량선량은 ICRP 권고 선량이하로, 불임 및 2차 암 발생에 대한 우려 수준은 현저히 낮지만 향후 유방암 발생 연령층이 낮아지고, 토모테라피와 같이 고정밀 영상유도장치를 이용한 방사선치료가 발달할수록, 가임기 여성 환자의 난소산란선량에 대한 임상적 추적조사가 더욱 필요할 것으로 사료된다.

• Journal of Plant Biotechnology
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• 제5권3호
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• pp.173-179
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• 2003

The combination of a radiation technique with an in vitro culture system was appiled to develop submergence tolerant rice. The 3,000 $M_3$ lines with an average 80 percent of fertile grain were utilized for the selection of submergence tolerance. Salt tolerant lines were selected based on high plant height, root length and root number after submergence in plastic pots. Of the lines tested, the tolerant line (403-6) showed a dramatic difference in morphological traits under submergence compared to its original variety (Dongjinbyeo). It was suggested that genetic variations between the original variety and $M_3$-403-6 did exist. The levels of $\alpha$-amylase and alcohol dehydrogenase activities were significantly increased in the mutant line compared to its original variety. The mutant with greater tolerance showed less electrolyte leakage indicating a greater membrane integrity and better survival. Also, this line was much more resistant to a salt stress of $1.25\%$ than the original variety. The proline level of the line was significantly (p<0.01> higher than that of the original variety. The relationships between the inhibition of growth caused by stress and the physiological changes in the plant cell were discussed.

• 대한핵의학회지
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• 제28권2호
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• pp.227-233
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• 1994

Irradiation of 20mg of natural $Dy(NO_3)_3$ in a neutron flux of $2{\times}10^{13}n/cm^2$ sec for 4 hours gave 5.76 Ci of $^{165}Dy$(specific activity, 610mCi/mg Dy) with high radionuclidic purity (>99.9 %). $^{165}Dy-MA$ was prepared in a quantitative yield by reacting the aqueous solution of $^{165}Dy(NO_3)_3$ with sodium borohydride solution in 0.2N NaOH. Coulter particle analyzer exhibited mean particle size of $2.6{\mu}m$ (range $1{\sim}6{\mu}m$), Even though the $^{165}Dy-MA$ suspension in saline was stored at $37^{\circ}C$ for 24 hours or autoclaved at $121^{\circ}C$ for 30minutes, there was no significant change in particle size and leakage problem indicating the prepared $^{165}Dy-MA$ is sufficiently stable. In-vivo retention studies were carried out by administering $^{165}Dy-MA$ into the knee joint space of normal rabbits. Gamma camera analysis showed high retention in joint space of normal rabbits. Gamma camera analysis showed high retention in joint space even at 24 hours after administration (> 99.9%). The ease with which the $^{165}Dy-MA$ can be made in the narrow size range and their high invitro and vivo stability make them attractive agents for radiation synovectomy.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.90-95
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• 2003

환형기체(Annulus Gas) 계통의 화학적 관리는 계통 재질의 건전성 확보와, 계통내 냉각재 또는 감속재 중수 유입 여부 감지 및 방사선량 저감화 등을 통하여 설비의 안전성과 신뢰성을 유지하는데 목적이 있다. 환형기체 계통의 화학 관리절차서 중 CO_2$ 규격 관리는 계통 재질의 건전성 확보와 방사선량 증가에 직결되기 때문에 고순도의 품질 보증이 요구되고 있다. CO_2$의 순도가 기준 값에 미달될 경우는 계통내에 직접적인 영향을 줄뿐 아니라 주변 환경으로의 오염 가능성도 상존하기 때문에 불순물의 정량관리는 매우 중요하다. 따라서 중수로 환형기체 계통에 공급되는 CO_2$ 중의 C, N_2$ 및 Ar등의 농도분석을 통하여 계통내에서 생성 될 수 있는 방사능 inventory를 평가하였으며 CO_2$의 불순물 관리 최적화와 중수로에서 생성되는 기체 방사성 폐기물 관리에 유용한 정보로 사용 될 수 있을 것이다.

• 한국광학회지
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• 제19권1호
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• pp.9-14
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• 2008

본 논문에서는 테라헤르츠 대역에서 동작하는 새로운 구조의 Yagi-Uda 안테나를 설계하였다. 제안한 Yagi-Uda 안테나는 안테나의 driver를 반 파장 다이폴이 아닌 전 파장 다이폴을 사용함으로써 공진주파수에서 $2000{\Omega}$ 정도의 높은 입력 저항을 얻을 수 있었다. 바이어스 선에 Photonic Bandgap 구조를 적용하여 바이어스 선로로의 전류누설을 최소화 하였고, 안테나를 얇은 기판에 설계함으로써 기판의 비유전율로 인한 안테나의 임피던스 저하를 막고 Yagi-Uda 안테나 고유의 단방향 지향적인 복사특성을 나타나게 하였다. 따라서 제안한 Yagi-Uda 안테나는 포토믹서와의 임피던스 부정합 문제를 개선하여 테라헤르츠파의 출력을 증가 시킬 수 있을 것이라 예상한다.

• Investigative Magnetic Resonance Imaging
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• 제26권1호
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• pp.10-19
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• 2022

Purpose: To evaluate whether the added value of contrast leakage information from dynamic susceptibility contrast magnetic resonance imaging (DSC MRI) is a better prognostic imaging biomarker than the cerebral blood volume (CBV) value in distinguishing true progression from pseudoprogression in glioblastoma patients. Materials and Methods: Forty-nine glioblastoma patients who had undergone MRI after concurrent chemoradiotherapy with temozolomide were enrolled in this retrospective study. Twenty features were extracted from the normalized relative CBV (nCBV) and extraction fraction (EF) map of the contrast-enhancing region in each patient. After univariable analysis, we used multivariable stepwise logistic regression analysis to identify significant predictors for differentiating between pseudoprogression and true progression. Receiver operating characteristic (ROC) analysis was employed to determine the best cutoff values for the nCBV and EF features. Finally, leave-one-out cross-validation was used to validate the best predictor in differentiating between true progression and pseudoprogression. Results: Multivariable stepwise logistic regression analysis showed that MGMT (O⁶-methylguanine-DNA methyltransferase) and EF max were independent differentiating variables (P = 0.004 and P = 0.02, respectively). ROC analysis yielded the best cutoff value of 95.75 for the EF max value for differentiating the two groups (sensitivity, 61%; specificity, 84.6%; AUC, 0.681 ± 0.08; 95% CI, 0.524-0.837; P = 0.03). In the leave-one-out cross-validation of the EF max value, the cross-validated values for predicting true progression and pseudoprogression accuracies were 69.4% and 71.4%, respectively. Conclusion: We demonstrated that contrast leakage information parameter from DSC MRI showed significance in differentiating true progression from pseudoprogression in glioblastoma patients.

• 센서학회지
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• 제22권1호
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• pp.71-75
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• 2013

Nuclear containment building is used as second blockage to protect us from a radiation leakage caused by the natural disaster or any accidents, so it's safety is important and must be kept with continuous surveillance. In this study, we measured the strain of a nuclear containment building's wall by using FBG sensor and investigated the structural safety of a nuclear containment building. 50 FBG strain sensors and 18 FBG strain sensors were attached on the side wall and upper dome of a nuclear containment building, respectively. We measured the strains of the outside concrete wall during the Structural Integrity Test (SIT) of a nuclear containment building. The strain of an upper dome was larger than that of a side wall, about $200{\mu}{\varepsilon}$. And the very small strain was measured at vertical direction of a side wall. These experimental results were used to evaluate the structural health of nuclear containment building.

• 한국안전학회지
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• 제31권5호
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• pp.54-60
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• 2016

In this study, tank truck incidents of road transport of hazardous materials to experimental investigated the potential fire hazard. Real scale fire was to perform experiments for on this qualitative and quantitative data collection and analysis. Particularly affected by radiant heat from the flames caused and damage estimates range investigated accordingly. Flame temperature, internal temperature of tank and emitted radiation from the flames was investigated. The flame of light oil spill caused a fire at a temperature of about $300^{\circ}C$ high in comparison with the methanol by combustion of diesel and methanol, according to the difference, the flame duration changes varies depending on the Burning rate. Depending on spill rate(30, 60, 90 and $120{\ell}/min$) and the longer the duration of the flame important factors for the internal temperature of tank lorry rise was found. Road accident in a fire caused by leakage of hazardous was could the higher the damaged. Therefor, Fire suppression activities should be required in particular to be around.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.37-43
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• 2014

Nuclear power plants(NPPs) are consisted of power production functions and safety functions preventing leakage of radiation. Operators working in NPPs shall maintain these functions during an operation period through various activities such as improvement & modification, corrective maintenance, preventive maintenance and surveillance test. According to the performance of these work activities, there are configuration changes in NPPs systems. Its changes cause the increase of safety risks(CDF) and plant trip risks. Recently, the importance of risk management is increasing gradually in the operation process of NPPs. Therefore, this paper presents the work management methods using the various risk monitoring systems during power operation and overhaul period. Also this paper suggests the optimum application ways of risk systems for work management.

• Journal of electromagnetic engineering and science
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• 제15권4호
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• pp.219-223
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• 2015

In this paper, a miniaturized radio frequency choke (RFC) using modified stubs is proposed to improve isolation characteristics in a multiple-input-multiple-output (MIMO) antenna system. The proposed RFC, based on the LC resonance, is designed to suppress the leakage current that leads to the degradation of antenna diversity performances in the MIMO antenna configuration. The proposed RFC is composed of two open stubs that are implemented on the top of the ground plane and miniaturized by adding a slit structure on the ground plane. The MIMO antennas are also designed to verify isolation performance in the LTE 2300 band (2,300-2,400 MHz). The MIMO antennas perform well with low reflection coefficient characteristics and high isolation characteristics in the whole LTE 2300 band. To evaluate the isolation in the MIMO system, the envelope correlation coefficient (ECC) is calculated, and the value is less than 0.08. The achieved ECC is regarded as a reasonable result for improving isolation performance in the frequency range of 2,300-2,400 MHz; also, radiation patterns of antenna elements are maintained regardless of the presence of RFC.