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전뇌(Whole Brain)치료 시 Field-in-Field Technique 적용에 관한 고찰
김보겸,이제희,정치훈,박흥득,Kim Bo Kyoum,Lee Je Hee,Jung Chi Hoon,Pack Heung Deuk 대한방사선치료학회 2005 대한방사선치료학회지 Vol.17 No.1
Purpose : Uniform dose distribution of the target volume is very important in the radiation treatment. We will evaluate the usefulness of Field-in-Field Technique use to get uniform dose distribution of the target volume and try to find Apply possibility out to a whole brain treatment patient of various thickness. Material and method : We compare the dose distribution when we applied Field-in-Field Technique and parallel opposed fields technique. establish the treatment plan to a phantom(acryl 16cm spheral phantom) and do the measurement, assessment use the TLD and Low sensitivity film. Also the assessment did Apply possibility of Field-in-Field Technique to 20 patient object of various thickness. Result : In the case to use the parallel opposed fields at the whole brain treatment $10-12\%$ high dose region appeared but reduce to $3-4\%$ lesses when we used the Field-in-Field technique. We could get similar numerical value the film and TLD measurement result also. The change of the dose distribution appeared to its ${\pm}1{\sim}2\%$ although it applied such Field-in-Field technique to various patient so that we were identical. Conclusion : We can get uniform dose distribution of in the treatment region if we apply the Field-in-Field technique at the whole brain treatment. Also alternate can play the role of the wedge filter and 3D compensator and We are thought by minimizing the obstacle to be happened due to the high dose region when radiation treatment.
실내 식물과 전기적 접지를 이용한 공공 흡연장 토양의 카드뮴 제거
이규원(Gyu Won Lee),김보겸(Bo Gyeom Kim),김예진(Ye Jin Kim),조정욱(Jeong Wook Jo),김재훈(Jae Hun Kim),양성우(Sung Woo Yang),김승준(Seung Jun Kim),김이령(Yi Ryung Kim),손동화(Dong Hwa Son),김형주(Hyung Joo Kim) 대한환경공학회 2024 대한환경공학회지 Vol.46 No.3
목적: 본 논문에서는 중금속으로 오염된 흡연장의 토양에 실내식물과 전기적 지면 접지를 적용하여, 식물의 토양 내의 중금속 흡수를 확인하였다. 이 결과를 통하여, 중금속 등으로 오염된 각종 토양의 정화에 실내식물의 활용성을 높이고자 하였다. 방법: 흡연장내 조성된 화분의 토양을 채취하여 일반화분과 전기적 접지(electrical grounding)가 적용된 2종의 화분을 실내에서 구성하고, 여기에 강낭콩(Phaseolus vulgaris) 씨를 식재하였다. 식재 후 30일간, 각 화분의 식물 생장 관찰을 진행하였다. 30일간 재배 후, 재배 토양의 TOC (Total Organic Carbon) 및 metagenomics 분석을 진행하였다. 또한 재배 토양의 중금속 농도 변화를 확인하고자 ICP-MS를 사용하여 토양과 식물내부의 카드뮴 농도를 측정하였다. 결과 및 토의: 줄기 길이 생장 측정률을 측정한 결과, 30일 기준 전기적 지면 접지 적용 식물이 비접지 식물에 비해 48.2 ± 2.3% 높게 확인되었다. TOC 분석 결과, 접지 화분의 토양내 TOC가 대조군, 비접지 토양에 비해 각각 3.08 ± 1.22%, 2.3 ± 0.1% 높게 확인되었다. ICP-MS 분석 결과, 전기적 지면 접지를 적용한 식물내의 카드뮴 농도가 0.33 ± 0.018 μg/kg으로 가장 높았다. 또한, 대조군 토양 시료에 비해 식물이 존재하는 비접지, 접지 토양의 평균 카드뮴 농도가 각각 10 μg/kg 정도 낮게 나타났다. Metagenomics 분석 결과, 전기적 지면 접지를 적용한 토양에서 중금속에 대한 biomineralization 기능을 갖는 것으로 알려진 Nocardioides sp., Streptomyces sp., Sphingomonas sp. 등이 확인되었다. 따라서 전기적 지면 접지 적용을 통한 식물의 생육 활성도 증가는 식물 뿌리의 exudate 분비 증가를 유도하여 TOC 및 미생물 군집에 영향을 주는 것으로 보이며, 이를 통해 식물의 토양내 중금속 흡수를 촉진한 것으로 판단된다. 결론: 연구결과, 실내식물을 이용한 흡연장 토양에서의 카드뮴 흡수 및 제거가 가능하였으며, 식물의 전기적 접지 적용을 통해 제거 효과를 증가시킬 수 있었다. 따라서 지면과 전기적으로 절연된 화단의 식물에 전기적 지면 접지를 적용 시, 기존 식물의 생육기반 토양정화와 함께 전기화학적 비료 효과를 통한 식물의 생육 활성화의 유도가 가능할 것으로 판단되며, 이를 통한 새로운 토양 오염 정화방법의 적용이 가능할 수 있을 것이다. Objectives : In this study, the absorption of heavy metals in the soil from smoking areas using indoor plants and electrical grounding was investigated to increase the utility of indoor plants for soil decontamination. Methods : Soil from plant pots in a smoking area was collected for the experimental plant pot preparations. Some of the prepared pots were connected to electrical ground via an electrode. Kidney beans (Phaseolus vulgaris) were seeded, and their growth were observed. After 30 days of the cultivation, TOC (Total Organic Carbon), and metagenomics profiles in the soil was analyzed. To estimate the behavior of the heavy metals in soil and plants, Cadmium concentrations in the samples were analyzed using ICP-MS (Inductively Coupled Plasma-Mass Spectrometry). Results and Discussion : The connection of the electrical ground to the plant pot induced the rapid growth of plant (48.2 ± 2.3% increase in stem growth), compare to the plant in the pot without the electrical ground. TOC analysis showed that the soil from the grounded pots showed the highest value, compared to the control soil (3.08 ± 1.22%), and the soil from the pot without ground connection (2.3 ± 0.1%). The ICP-MS analysis indicated that the plant body in the grounded pot had the highest cadmium concentration at 0.33 ± 0.018 μg/kg. Using the metagenomic analysis, biomineralization related bacterial species (Nocardioides sp., Streptomyces sp., Sphingomonas sp. etc.) were identified from the grounded soil sample. These results suggested that the indoor plant cultivation with the electrical ground connection as an electrical fertilizer enhances the cadmium absorption by plant, exudate secretion from the plant root, and bacterial flora change in the rhizosphere. Conclusion : Cadmium in the soil from the smoking area was absorbed by indoor plant with the electrical ground. Therefore, the application of the electrical ground connection (earth) to the electrically insulated outdoor plant pots might enhance the plant growth rate and physiological activity. This application could be a novel soil decontamination method using plants.
액체로켓엔진 재순환 유로에서의 수격현상에 관한 실험적 연구
김보겸(Bokyem Kim),홍문근(Moongeun Hong),이지성(Jisung Lee),김정한(Junghan Kim) 한국추진공학회 2021 한국추진공학회지 Vol.25 No.2
In a liquid rocket engine system, the flow of oxidizer into the combustion chamber is controlled by the main oxidizer shut-off valve. When the valve is closed, the oxidizer flows via the recirculation line, not into the combustion chamber. In this situation, the measured pressure could be much higher than a design value because of the water hammer phenomenon. In this paper, the experiments on the water hammer in the recirculation line with different initial conditions were conducted in order to study the pressure wave produced in each case. According to the experimental results, characteristics of the pressure wave in the recirculation line depend on the initial condition. To be specific, the pressure surge is maximized in case that the shock is condensation-oriented in the end of the recirculation line.