• Research in Plant Disease
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• v.8 no.4
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• pp.199-206
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• 2002

It was investigated on the relationship of the rice blast epidemics and the real-time meteorological factors, at the experimental paddy field in 1997. Weather factors(temperature, relative humidity, irradiation, precipitation, the direction of wind, wind speed, soil temperature and leaf-wetness, etc) were measured by using the automated weather station. The most influenced weather factor to blast epidemics, was the average max-temp($R^2$= 0.95) during 10 days before leaf blast epidemics, while the least thing was wind speed($R^2$= 0.24). The most potential weather factors correlated with the blast epidemics were T-ave(average temperature), T-max(maximum temperature), RH(Relative Humidity) and RD(Relative Humidity > 90% hrs). A statistics model(the regression equation) of the blast epidemics with the potential weather factors, was established as tallows ; Y = -3410.91 - 23.91 $\times$ T-ave ＋ 28.56 $\times$ T-max ＋ 41.0 $\times$ RH - 3.75 $\times$ RD, ($R^2$= 0.99). (T-ave >= 19$^{\circ}C$, T-max - T-ave >= 5.2$^{\circ}C$ and RH% >= 90.4%). According to the fitness test($\chi$$^2$) of the model, the observed blast disease severity was quite close to those expected.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.442-453
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• 2013

A large-scale high-temperature thermal energy storage(TES) was numerically modeled and the heat loss through storage tank walls was analyzed using a commercial code, FLAC3D. The operations of rock cavern type and above-ground type thermal energy storages with identical operating condition were simulated for a period of five consecutive years, in which it was assumed that the dominant heat transfer mechanism would be conduction in massive rock for the former and convection in the atmosphere for the latter. The variation of storage temperature resulting from periodic charging and discharging of thermal energy was considered in each simulation, and the effect of insulation thickness on the characteristics of heat loss was also examined. A comparison of the simulation results of different storage models presented that the heat loss rate of above-ground type TES was maintained constant over the operation period, while that of rock cavern type TES decreased rapidly in the early operation stage and tended to converge towards a certain value. The decrease in heat loss rate of rock cavern type TES can be attributed to the reduction in heat flux through storage tank walls followed by increase in surrounding rock mass temperature. The amount of cumulative heat loss from rock cavern type TES over a period of five-year operation was 72.7% of that from above-ground type TES. The heat loss rate of rock cavern type obtained in long-period operation showed less sensitive variations to insulation thickness than that of above-ground type TES.

• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.232-242
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• 2007

Background : The safety and efficacy of trabeculectomy with Mitomycin C (MMC) for surgical treatment in aphakic and pseudophaic eyes were retrospectively evaluated. Materials and Methods : The authors reviewed 51 eyes of 45 patients who had been followed up for at least 6 months after trabeculectomy using MMC for aphakic and pseudophakic eyes. The success rate and complications were analyzed. The success criteria included intraocular pressures of 21 mmHg or less with or without glaucoma medications and no loss of light perception. Surgical failure was defined as a postoperative loss of light perception in patients with preoperative vision better than light perception, additional glaucoma surgery, or phthisis bulbi in patients with preoperative vision of no light perception. Results : The average follow up period was 27.7 months and the intraocular pressure was controlled under 21 mmHg in 36 eyes of 51 (70.6%) after the procedure with or without medication for glaucoma. Using the Kaplan-Meier survival analysis, the cumulative success rate at the 3-, 6-, 12-, 24- and 36-month intervals were 98.0%, 94.1%, 91.9%, 83.4% and 75.5%, respectively. The complications observed were hyphema (4 eyes), serous choroidal detachment (4 eyes), hypotony (3 eyes), and endophthalmitis (1 eye). Conclusion : Trabeculectomy using Mitomycin C for the treatment of aphakic and pseudophaic eyes was safe and effective.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.368-372
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• 2008

Composting is a good strategy for management of livestock manure. However, it leads to large ammonia emissions and has a potential phosphorus runoff due to high content of soluble phosphorus. The objective of this study was to evaluate the efficiency of alum on reducing ammonia emissions and stabilizing phosphorus during composting of pig manure. For this study, alum was applied at rates of 0 (No-Alum), 1.0 (Alum-L), and 3.0 (Alum-H) g Al $kg^{-1}$ pig manure and sawdust mixture (fresh matter basis). The thermophilic stage was quickly achieved in Alum-L and No-alum treatment, but it was delayed to 5 days in Alum-H treatment. The thermophilic stage was maintained for 2 weeks in all treatment. The pH of compost treated with alum remained below 8.0 for the 35 d but it was above 8.0 in No-Alum treatment. For the first 15 days of composting process, 93, 87, and 58% of total ammonia emissions were occurred in No-Alum-L and Alum-H, respectively. The Alum-H and Alum-L treatments reduced $NH_3$ volatilization by 31 and 78% compared with No-Alum treatment. Alum treatments shifted manure P form $H_2O$ and $NaHCO_3$ extractable P into NaOH extractable P which is very stable under acid and alkaline condition. Therefore, alum is a good chemical amendment for reducing ammonia emission during composting and potential losses of P following compost applications.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.483-494
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• 2007

The properties of fracture system on road-cut slopes along the Busan-Ulsan express way under construction are investigated and analyzed. Fracture spacing distributions show log-normal form with extension fractures and negative exponential form with shear fractures. Straight line segments in log-log plots of cumulative fracture length indicate a power-law scaling with exponents of -1.13 in site 1, -1.01 in site 2 and -1.52 in site 3. It is likely that the stability and strength of rock mass are the lowest in site 1 as judged from the analyses of spacing, density and inter-section of fractures in three sites. In contrast, the highest efficiency of the fracture network for conducting fluid flow is seen in site 3 where the largest cluster occupies 73% through the window map. Based on the field survey data, this study modified weighting values of the RMR system using a multiple regression analysis method. The analysis result suggests a modified weighting values of the RMR parameters as follows; 18 for the intact strength of rock; 61 for RQD; 2 for spacing of discontinuities; 2 for the condition of discontinuities; and 17 for ground water.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.12-18
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• 1991

Three-dimensional nonlinear sloshing effects due to tank motions are simulated by solving boundary value problem using the panel method based on boundary integral technique. While Shinkai used boundary elements on which source strengths vary linearly between nodes, the source of constant strength is distributed on each triangular panel in the present study. The source strength at each time step is determined by solving the Fredholm integral equation of the second kind obtained from Green's theorem. To avoid cumulative numerical errors as time elapses, Adam-Bashforth-Moulton method is employed. Numerical examples for the case of partially filled spherical tank on board oscillating in harmonic sway mode or pitch mode are solved. The elevation of the free surface is compared with the result by Shinkai and confirmed in good agreement during early time. The input and the output energy are comparatively evaluated to check the overall accuracy of the present numerical scheme. Although some leakage of energy are found as time marches, it is plausible when we take into account nonlinearities of the problem and the number of panels of the model.

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.43-52
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• 1998

서방형 돼지성장호르몬(sustained-release formulation of porcine somatotropin, PST-SR)을 1주 간격으로 6차례 피하 및 근육주사하고 혈액과 조직중의 돼지 성장호르몬(PST)과 insulin-like growth factor 1(IGF-1)의 농도를 측정하여 다음과 같은 결과를 얻었다. 대조군의 혈중 PST와 IGF-1의 농도는 각각 2.41과 95.2 ng/ml 이었다. 1. PST-SR을 투여한 후 PST의 혈중농도는 8시간만에 최대에 도달하여(30 ng/ml) 곧 감소하였다. 혈중농도 반감기(decay half life)는 91~227시간이었다. IGF-1의 혈중농도는 투여후 12시간에 최대에 도달하였으며(165 ng/ml), 이후 서서히 감소되었고 반감기는 77~99시간이었다. 2. 혈중 PST농도-시간의 자료는 제재에서 PST가 유리되는 과정에는 두단계 즉, 투여후 24시간까지의 유리속도가 빠른 단계와 그 이후의 유리속도가 느린 단계가 있음을 보여주었다. 3. 여섯번의 반복투여기간에는 PST의 혈중농도는 투여직후 증가하여 24시간 이후 다음 투여전까지 지속적으로 감소되는 패턴이 반복되었고, 최종투여후 1주일경에는 정상수준으로 회복되었다. 반면에 투여가 반복됨에 따라 매 투여직후의 PST의 혈중 최고치는 다소 증가되는 경향을 보였다(20~40 ng/ml). IGF-1의 혈중농도는 투여가 반복됨에 따라 누적적인 증가현상이 뚜렷하였으며, 이후 2주일후 까지도 정상농도보다 높게 유지되었다(200ng/ml). 임상용량 투여군에서 PST 및 IGF-1의 혈중농도는 투여경로에 따른 차이는 나타나지 않았다. 4. 최종(6번째) 투여후 6, 8, 10, 14일에 조사한 간장, 신장, 소장, 근육, 지방 및 주사부위의 조직중의 PST 농도는 6일째에 이미 대조군 수준으로 회복되었다. IGF-1의 경우 최종투여후 6일에는 간장, 신장, 소장, 지방조직에서 정상보다 높은 농도로 잔류하나 이후 14일까지 모두 대조군 수준으로 감소되었다. 5. 이상의 결과는 본 실험에서 사용된 서방형 PST제제는 최소 1주간 유효성이 유지되며, 동시에 PST는 투여 6일째에, IGF-1은 투여후 14일에 정상수준으로 회복됨을 보여주고 있다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.143-148
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• 2020

In the case of a system that detects and controls the phase of an alternating voltage, the analog control method compensates the phase offset part by filtering for the detected phase and applies it to the control. However, in the digital control method, precise control cannot be achieved due to an error between the operating frequency of the microprocessor or the microcontroller and the input phase time when controlled using such phase detection. In general, when the method used is a certain time, the accumulated error is compensated and adjusted at random. To solve this problem, a method of detecting a zero point in real time and compensating for the operating frequency of the microprocessor is needed. Therefore, the research to be performed in this paper to reduce these errors and apply them to precise digital control is as follows. 1) Research on how to implement Zero Crossing Detection algorithm through simulation modeling to compensate the zero point to match the operating frequency through detection. 2) A study on the method of detecting zero points in real time through the Zero Crossing Detection design using a microcontroller and compensating for the operating frequency of the microprocessor. 3) A study on the estimation of the rotor position of BLDC motors using the Zero Crossing Detection circuit.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.513-521
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• 2019

With rapid climate change and increasing global warming, the distribution of evergreen broad-leaved trees (EBLTs) is gradually expanding to the inland regions of Korea. The aim of the present study was to analyze the survival rate of 148 EBLT plantations measuring 180 ha and to determine the optimal plantation size that would help in coping with climate change in the warm, temperate climate zone of the Korean peninsula. For enhancing the reliability of our estimated survival model, we selected a set of 11 control variables that may have also influenced the survival rates of the EBLTs in the 148 plantations. The results of partial correlation analysis showed that the survival rate of 67.0±26.9 of the EBLTs in the initial plantation year was primarily correlated with plantation type by the crown closure of the upper story of the forest, wind exposure, and precipitation. For predicting the probability of survival by quantification theory, 148 plots were surveyed and analyzed with 11 environmental site factors. Survival rate was in the order of plantation type by the crown closure of upper story of the forest, wind exposure, total cumulative precipitation for two weeks prior to planting, and slope stiffness in the descending order of score range in the estimated survival model for the EBLTs with the fact that survival rate increased with shade rate of upper story to some extent.

• Journal of Radiation Protection and Research
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• v.29 no.2
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• pp.141-150
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• 2004

Dose rate characteristics of cosmic radiation field at flight altitudes were analyzed and the route doses to the personnels on board due to cosmic-ray were calculated for Korean-based commercial international airline routes using CARI-6. Annual individual doses to aircrew and the collective effective dose of passengers were estimated by applying the calculated route doses to the flight schedules of aircrew and the air travel statistics of Korea. The result shows that the annual doses to aircrew, around 2.62 mSv, exceed the annual dose limit of public and are comparable to doses of the group of workers occupationally exposed. Therefore it is necessary to consider the frequent flyers as well as the aircrew as the occupational exposure group. The annual collective dose to 11 million Korean passengers in 2001 appeared to be 136 man-Sv. The results should be modified when the dose rates of cosmic radiation at high altitude are revised by taking into account the changes in the radiation weighting factors for protons and neutrons as given in ICRP 92.