• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.250-254
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• 2011

The study was carried out to evaluate the affect of proton beam radiation on production of bulbil and tuber including change of endogenous gibberellins, of Dioscorea opposita Thunb. The yield of bulbils and tubers from non- and irradiated D. opposita Thunb at doses of 5, 10, 15 and 20 Gy were determined. Endogenous gibberellins were also quantified by GC/MS analysis. D. opposita tubers irradiated at 15 Gy produced higher bulbil production than non-irradiated plants. Enlarged bulbil (above size diameter 4 mm) was significantly increased at 15 Gy. Bioactive endogenous $GA_4$ was dominant in bulbils and tubers irradiated with proton beam rather than $GA_1$. Major gibberellins biosynthetic pathways in bulbils and tubers of D. opposita plants were non C-13 hydroxylation route. From the results of this study, 15 Gy proton beam radiation was suggested as an optimal dose that can produce high amounts of bulbil for mass production of D. opposita plant.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.2
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• pp.209-217
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• 2005

The energy balance of the surface layer of the water (the Yellow Sea, the East China Sea and the East Sea) was examined using satellite data. Variations of the net heat flux were similar to those of the latent heat flux which was more intensive than the sensible heat flux. The sensible heat flux was affected the difference between the sea surface temperature and the air temperature and was less important over the Yellow Sea. The maximum of the latent heat flux occurred in autumn when the air is drier and the wind is stronger. The shortwave radiation flux decreased with the latitude and depended on the cloudiness as the longwave radiation flux does. Annual variations of heat fluxes show that the latent heat flux was more intensive over the East China Sea than the East Sea and the Yellow Sea, while the spatial differences of the other heat fluxes were weak.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2346-2352
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• 2020

Dual-energy x-ray absorptiometry (DXA) is the noninvasive method to diagnose osteoporosis disease characterized by low bone mass and deterioration of bone tissue. Many global companies and research groups have developed the various DXA detectors using a direct photon-counting detector such as a cadmium zinc telluride (CZT) sensor. However, this approach using CZT sensor has some drawback such as the limitation of scalability by high cost and the loss of efficiency due to the requirement of a thin detector. In this study, a SiPM based DXA system was developed and its performance evaluated experimentally. The DXA detector was composed of a SiPM sensor coupled with a single LYSO scintillation crystal (3 × 3 × 2 ㎣). The prototype DXA detector was mounted on the dedicated front-end circuit consisting of a voltage-sensitive preamplifier, pulse shaping amplifier and constant fraction discriminator (CFD) circuit. The SiPM based DXA detector showed the 34% (at 59 keV) energy resolution with good BMD accuracy. The proposed SiPM based DXA detector showed the performance comparable to the conventional DXA detector based on CZT.

• Korean Journal of Remote Sensing
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• v.6 no.2
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• pp.75-88
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• 1990

NOAA 위성의 narrow-band AVHRR(Advanced Very. High Resolution Radiometer) 적 외선 채널과 broad-band 0.2 - 50$\mu\textrm{m}$ 영역의 ERBE(Earth Radiation Budget Experiment) scanning instrument에 의하여 관측된 radiance로부터 추정된 지구의 대기 외장파복사량 (Outgoing Longwave Radiation:OLR) 이 비교조사되었다. 이를 위하여 1985년 4월, 7월, 10월과 1986년 1월에 위성에서 관측된 radiance를 각각 이용하였고 비교된 OLR은 위도와 경도가 각각 2.5$^{\circ}$ 간격으로 구분된 grid내에서 일치(collocate)시켜 지역별(zonal), 그리고 전지구(global)규모 로 비교되었다. ERBE와 AVHRR에 의하여 각각 추정된 OLR값의 차(ERBE minus AVHRR)에 의한 분석 결과는 주간의 경우 -1~2 W/m$^2$의 값과 야간의 경우 4~7 W/m$^2$의 값으로 비교적 좋은 일치를 보였지만 이들의 RMS는 하절(6월)에 12 W/m$^2$와 동절(12월)에 5 W/m$^2$의 값으로 다소 높은 차이를 보였다. 한편, 이들 OLR값을 관측지역에 따라 큰 차 이를 나타내어 사막지역과 아열대고기압(subtropical ocean)대에서는 상반된 결과를 보였다. 이들 지역에 대한 차이는 지역적 기온구조와 지표온도의 영향을 다 고려하지 못하고 OLR 측정치를 도 출하는 대기복사모델(radiation model)의 regional systematic bias에서 기인된 것으로 해석된다. 즉 사막의 지표역전층에 대한 AVHRR과 해면의 대기구조에 대한 ERBE의 OLR은 상반된 영향을 보였다.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.825-836
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• 2019

One of the most challenging safety precautions for workers in dynamic, radioactive environments is avoiding radiation sources and sustaining low exposure. This paper presents a sampling-based algorithm, DL-RRT*, for minimum dose walk-path re-planning in radioactive environments, expedient for occupational workers in nuclear facilities to avoid unnecessary radiation exposure. The method combines the principle of random tree star ($RRT^*$) and $D^*$ Lite, and uses the expansion strength of grid search strategy from $D^*$ Lite to quickly find a high-quality initial path to accelerate convergence rate in $RRT^*$. The algorithm inherits probabilistic completeness and asymptotic optimality from $RRT^*$ to refine the existing paths continually by sampling the search-graph obtained from the grid search process. It can not only be applied to continuous cost spaces, but also make full use of the last planning information to avoid global re-planning, so as to improve the efficiency of path planning in frequently changing environments. The effectiveness and superiority of the proposed method was verified by simulating radiation field under varying obstacles and radioactive environments, and the results were compared with $RRT^*$ algorithm output.

• The Journal of the Acoustical Society of Korea
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• v.42 no.2
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• pp.83-93
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• 2023

Trapezoidal corrugated plates are often treated as orthotropic plates to simplify the modelling of the corrugation. However, this simplification is not valid at high frequencies in which the localized vibration within the parts of corrugation takes place. In this study, the vibrational and acoustical characteristics of corrugated plates are investigated up to high frequencies by means of the wavenumber domain numerical approach. Based on the findings from this numerical analysis, an approximate method to predict vibro-acoustic characteristics of corrugated plates is proposed. This approximate model consists of four equivalent plates which can represent global and local behaviours of corrugated plates. The radiation efficiency of corrugated plates is predicted from the approximate model and validated through the comparison with those of the numerical method.

• Journal of Microbiology
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• v.43 no.3
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• pp.308-312
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• 2005

The global RNA transcription profiles of Bacillus lentimorbus WJ5 under an in vitro co-culture with Colletotrichum gloeosporioides were analyzed in order to study the antagonistic bacteria-fungi interactions. Using a filter membrane system, B. lentimorhus WJ5 was exposed to the spores of C. gloeosporioides at the late exponential stage. The transcription profiles of the B. lentimorhus WJ5, both with and without a challenge from C. gloeosporioides, were analyzed using custom DNA chips containing 2,000 genome fragments. A total of 337 genes were expressed, with 87 and 47 up- and down-regulated, respectively. Of these, 12 genes, which were involved in central carbon metabolisms, and 7 from minor catabolism were relatively highly up-regulated (> 10 fold) and down-regulated (< 0.2 fold), respectively. Nine genes, which were thought to be related to the antifungal activity, were also up-regulated, but their levels were not so high (2.0 - 9.7 folds). From the results, during the early stage of the co-culture of B. lentimorbus WJ5 and C. gloeosporioides, nutrient competition seemed to occur; therefore, the genes from central carbon metabolisms could be up-regulated, while those from minor catabolism could be down-regulated.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.1
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• pp.11-14
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• 1988

Field study was conducted to evaluate the relationship between daytime net radiation (Drn) and global solar radiation (Rs) and to develop the empirical equation predicting daytime net radiation above corn canopy from observations of Rs and Ta (mean daily air temperature). The relationship between Drn and Rs under the cloudless day was Drn = 0.6659Rs and that under the cloudy (> 35% of possible sunshine) Drn = 0.729Rs. Thus, Drn/Rs Ratio under cloudless day was found to be lower than that under the cloudy day. Rs and Ta were used in the radiation balance equation to estimate Drn and the empirical model could be expressed as $Drn=[0.9Rs-(352-227{\times}10^{-10}{\times}Ta^4)]$ [1.11Rs/Rso - 0.05].

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.95-103
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• 2005

Purpose : In the radiosurgery, to obtain CT image to find more accurate tumor position during respiration, and using them, to increase the accuracy of radiation treatment by applying image guided. Materials and Methods : Using the self-made vacuum cushion for the body SRS, CT images were obtained three for each patient during respiration (shallow, inhalation, exhalation). They were transformed to the RTP computer and then were fused. Global GTVs were delineated on the fused images and more appropriated treatment planning was established. Results : We can find the tumor position is moving toward cranio-caudal with max 10 mm margin and volume is transformed. As a result from the comparision of DVH (pre & post radio surgery), we observed about 100% dose to tumor. Conclusion : BSRS was skeptical due to the tumor movement during respiration. More accurate by the combination of the development of immobilization devices and BSRS based on Image Guide, it will be applied to more cases for BSRS.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.1
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• pp.1-10
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• 1993

A brief description on the greenhouse gases, the greenhoue effect, sea level changes, forcing of climate, the history of Earth's changing climate based on the IPCC REPORT and the records of the recent variation of the climate in the Republic of Kore is presented here for help enhancing awareness of the issues. The climate of the Earth has the potential to be changed on all timescales by the fluctuations of the concentrations of radioactively active greenhouse gases, solar radiation, aerosols and albedo. However, the rate of the recent global warming seems to be larger and rapid than any have occurred thorughout recorded history enough to draw the world-wide attention and worry concerned with the theme of environment and development. There are still uncertainties in the predictions relating to the timing, magnitude and the pattern of the climatic change due to the current incomplete understanding of various aspects of the complex processes. Nonetheless, the scientific results avaliable is sufficient to allow for decisive precautionary measures to be taken.