• Nuclear Engineering and Technology
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• 제25권3호
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• pp.413-423
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• 1993

본 논문에서는 경수로 노심 용융사고시 1차계통의 압력이 높은 경우에 발생하는 격납용기 직접가열 현상에 대한 실험연구를 하였다. 실험은 고리 1,2호기와 영광 3,4호기의 1/30 축소규모와 고리 1,2호기의 1/20 축소규모를 실험모형으로 하여 수행되었으며, 고리 1,2호기의 경우 축소 규모에 따른 검증도 시도하였다. 실험의 주요 변수는 초기 압력 용기의 압력, 파열면적 및 캐비티의 구조 등이다. 실험결과로부터 캐비티 외부로의 용융노심 분사비율은 높은 초기압력과 큰 파열면적을 가진 경우가 더 높으며 캐 비티의 구조가 분사비율에 큰 영향을 미침을 알 수 있었다. 본 연구의 실험결과를 이용하여 분사비율에 대한 실험관계식을 무차원 유효시간의 함수로 도출하여 제시하였으며, 이 실험관계식은 본 실험결과 뿐만 아니라 한국 과학기술원의 실험자료 및 미국 BNL 실험결과와도 잘 일치하였다.

• Journal of Plant Biotechnology
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• 제34권1호
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• pp.47-53
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• 2007

To assess the risk of genetically modified (GM) rice on the agricultural ecosystem, agronomic characteristics, pollen longevity and outcrossing rate between GM (Iksan 483 and Milyang 204) and non-GM (their wild types and female parents) varieties were investigated using the bar gene as a tracer marker in paddy field. The agronomic characteristics of two GM rice were similar to their female-parents (non-GM rice) except heading date and 1,000 grain weight of Iksan 483, and they did not show a difference by the introgression of the bar gene as the genetic traits of rice varieties. Pollen viability was more than 90% just after shedding, and it was rapidly decreased below 50% at 5 minutes after shedding both GM and non-GM varieties. The Pollen longevity was lost after 30 minutes of anthesis. When the distance of gene flow from GM to non-GM rice detected to 6 m from the edge of GM rice plant, the maximum distance of pollen dispersal was 4.5m and 3.9m in Iksan 483 and Milyang 204, respectively, and that was increased in order of west, south, east, and north to the dominant wind direction, west-south. Mean outcrossing rate was very low as 0.003 and 0.001% within 1.5 m from the edge of Iksan 483 and Milyang 204, and the GM hybrids by the pollen dispersal did not detected over 4.5 m from the edge of GM rice plant. The results may help to establish the strategy which reduce the risk of pollen-mediated gene flow between GM and non-GM rice.

• 한국환경과학회지
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• 제25권5호
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• pp.635-644
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• 2016

Birds play a main role in the formation and change of forest structures as they are seed-dispersal agents. This study aims to identify birds consuming fruits and seeds of the tree and their associated fruits and seeds on Jeju Island in the context on the forest restoration in Korea. We conducted field surveys twice a month from 2013 to 2015 at nine study sites located across Jeju Island and collected available photographic and observation records. A total of 50 species of birds consuming fruits and seeds of the tree were identified and birds belonging to Bombycillidae, Pycnonotidae, Zosteropidae, Sturnidae and Fringillidae were confirmed as major birds consuming fruits and seeds of the tree. Gulping was the dominant type of feeding as well as crushing, but relationship between the size of a bird and the number of fruit and seed species used by the bird was not significant. We also documented that 118 fruit and seed species were consumed by birds and that shrubby fruits and seeds were more consumed by birds than those of other plant types. The relative consumption rate of fruits and seeds ranged from 0.02 to 0.44, but five species were the most important fruits and seeds for birds. Our finding suggest that avian frugivorous gulpers will benefit the seed dispersal, especially of five fruiting plants, providing useful baseline data for forest restoration and urban park design.

• Nuclear Engineering and Technology
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• 제42권1호
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• pp.17-36
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• 2010

In this study, we compare the mass release rates of radionuclides(1) from waste forms arising from the KIEP-21 pyroprocessing system with (2) those from the directly-disposed pressurized-water reactor spent fuel, to investigate the potential radiological and environmental impacts. In both cases, most actinides and their daughters have been observed to remain in the vicinity of waste packages as precipitates because of their low solubility. The effects of the waste-form alteration rate on the release of radionuclides from the engineered-barrier boundary have been found to be significant, especially for congruently released radionuclides. the total mass release rate of radionuclides from direct disposal concept is similar to those from the pyroprocessing disposal concept. While the mass release rates for most radionuclides would decrease to negligible levels due to radioactive decay while in the engineered barriers and the surrounding host rock in both cases even without assuming any dilution or dispersal mechanisms during their transport, significant mass release rates for three fission-product radionuclides, $^{129}I$, $^{79}Se$, and $^{36}Cl$, are observed at the 1,000-m location in the host rock. For these three radionuclides, we need to account for dilution/dispersal in the geosphere and the biosphere to confirm finally that the repository would achieve sufficient level of radiological safety. This can be done only after we have known where the repository site would by sited. the footprint of repository for the KIEP-21 system is about one tenth of those for the direct disposal.

• 분석과학
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• 제25권3호
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• pp.164-170
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• 2012

시아노아크릴레이트 훈증법은 비다공성 표면에 유류된 잠재지문을 현출할 때 효과적이다. 본 연구는, 진공챔버에서 시아노아크릴레이트를 훈증할 때 온도, 습도, 훈증 방법 등이 잠재지문 현출에 미치는 영향을 확인한 후 최적 반응 조건을 찾는데 있다. 진공챔버의 온도가 높을수록 시아노아크릴레이트 증발량은 증가했지만, 지문 융선에서 시아노아크릴레이트의 중합반응은 $30^{\circ}C$에서 가장 잘 일어났다. 상대습도가 40%, 50% 조건에서는 좋은 상태의 지문이 현출되었지만, 30%보다 낮거나 60%보다 높은 조건에서는 지문 융선에서 시아노아크릴레이트 중합반응 속도가 느려졌다. 진공챔버에서 시아노아크릴레이트를 자연적으로 증발시키는 방법보다는 $OMEGA-PRINT^{TM}$ dispersal pads와 수산화나트륨을 포함한 솜을 이용해 시아노아크릴레이트 훈증하는 방법이 효과적이란 사실을 확인할 수 있었다. 진공챔버에서 시아노아크릴레이트 처리시간은 상대습도에 비해 큰 영향을 주지 않았다.

• 한국산업융합학회 논문집
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• 제27권2_2호
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• pp.437-443
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• 2024

The purpose of radiological Dispersal Device(RDD) is to kill people by explosives and to cause radiation exposure by dispersing radioactive materials. And It is a form of explosive that combines radioactive materials such as Co-60 and Ir-192 with improvised explosives. In this study, we tested and evaluated whether it was possible to read the internal structure of an explosive using X-rays in a radioactive explosive situation. The improvised explosive device was manufactured using 2 lb of model TNT explosives, one practice detonator, one 9V battery, and a timer switch in a leather briefcase measuring 41×35×10 cm³. The radioactive material used was the Co-60 source used in the low-level gamma ray irradiation device operated at the Advanced Radiation Research Institute of the Korea Atomic Energy Research Institute. The radiation dose used was gamma ray energy of 1.17 MeV and 1.33 MeV from a Co-60 source of 2208 Ci. The dose rates are divided into 0.5, 1, 2, and 4 Gy/h, and the exposure time was divided into 1, 3, 5, and 10 minutes. Co-60 source was mixed with the manufactured explosive and X-ray image reading was performed. As a result of the experiment, the X-ray image appeared black in all conditions divided by dose rate and time, and it was impossible to confirm the internal structure of the explosive. This is because γ-rays emitted from radioactive explosives have higher energy and stronger penetrating power than X-rays, so it is believed that imaging using X-rays is limited By blackening the film. The results of this study are expected to be used as basic data for research and development of X-ray imaging that can read the internal structure of explosives in radioactive explosive situations.

• 한국자원식물학회지
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• 제28권1호
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• pp.101-110
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• 2015

부안지역 소나무 집단의 화분유동과 교배양식 모수를 추정하기 위하여 7개 microsatellite 표지로 모수, 주변 성목 및 종자에 대한 유전변이를 분석하였다. 이형접합도 기대치($H_e$)와 근교계수(F)는 각각 모수에서 0.614과 0.018, 종자에서 0.624과 0.087이며, 각 세대간에 차이는 없었다(P > 0.05). MLTR로 추정한 타가교배율($t_m$)은 0.967이며, 양친간 근연계수($t_m-t_s$)는 0.057, 부계상관($r_p$)은 0.012로 나타났다. 기존에 보고된 소나무의 동위효소 분석 결과에 비하여 타가교배율은 높고 근친교배 및 부계상관은 낮았으나, microsatellite 표지를 이용한 소나무류의 결과들과는 유사하였다. TwoGener로 추정한 최적 화분비산 모델은 유효밀도(d = 220 trees/ha)를 가정한 정규확산모델로 판명되었으며, 평균 화분비산거리(${\delta}$)는 11.42 m로 계산되었다. 화분원 유전적 분화(${\Phi}_{ft}$)는 0.021이며, Mental 검증에서 모수간 지리적 거리와 화분원의 유전적 분화는 상관성이 없는 것으로 나타났다(r = -0.141, P > 0.05). 부안지역 소나무 집단은 대부분의 화분이 가까운 거리에서 공급되지만, 화분수의 유전다양성이 높고 화분원의 유전적 차이가 작은 상태로 추정된다. 이러한 조건에서 완전한 임의교배가 이루어지기 때문에 종자의 유전자형이 다양하며 세대간 유전변이의 감소가 없는 것으로 사료된다.

• 식물병연구
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• 제19권2호
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• pp.114-117
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• 2013

To facilitate their spread, plant viruses have developed several methods for dispersal including insect and seed transmission. While insect transmission requires virus stability against insect digestion, seed-transmitted viruses have to overcome barriers to entry into embryos. Bean pod mottle virus (BPMV) is transmitted through seed at levels typically below 0.1%, but co-infection with Soybean mosaic virus (SMV) enhanced the seed transmission rate of BPMV in one experiment. In contrast, the rate of SMV seed transmission was not affected by BPMV co-infection. In a second preliminary study, the rate of SMV transmission was lower in an isoline of Williams 82 that contained a null mutation for the Kunitz trypsin inhibitor gene than in Williams 82. In this preliminary study, we observed that factors such as protease inhibitor expression and dual infection may affect the frequency of seed transmission of BPMV and SMV.

• Journal of Information Processing Systems
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• 제13권2호
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• pp.215-235
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• 2017

Foraging is a biological process, where a bacterium moves to search for nutriments, and avoids harmful substances. This paper proposes a hybrid approach integrating the bacterial foraging optimization algorithm (BFOA) in a radial basis function neural network, applied to image classification, in order to improve the classification rate and the objective function value. At the beginning, the proposed approach is presented and described. Then its performance is studied with an accent on the variation of the number of bacteria in the population, the number of reproduction steps, the number of elimination-dispersal steps and the number of chemotactic steps of bacteria. By using various values of BFOA parameters, and after different tests, it is found that the proposed hybrid approach is very robust and efficient for several-image classification.

• 한국응용곤충학회지
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• 제4권
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• pp.55-58
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• 1965

본문은 서울을 중심으로 한 주요교통로를 따라 솔칠혹파리의 피해선단지를 조사한 것이다. (1) 서울지방의 술잎혹파리 피해는 광주, 양수, 서파, 봉천, 고촌 등 동북방으로 널리 전파되어 있다. (2) 솔잎혹파리의 전파를 조장하는 인자로는 성충기의 향이 가장 관계가 깊은 것으로 관찰되었다. (3) 솔잎혹파리 피해선단지의 유충기생봉 솔잎혹파리 좀벌의 기생율은 서파의 $13.6\%$를 제외하고는 매우 높았다.