• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.1
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• pp.62-72
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• 1985

In order to find out the effects of seeding time on growth, dry matter production and nutritive content of Pioneer 931, Pioneer 988 and Piper, this study was carried out on the experimental field of Livestock Experiment Station in 1981-83. Seeding time were 7 with 14-day interval from April 16 to July 9. The results are summarized as follows: 1. It tool about 12 to 13 days from seeding to emergence in case of Mid-April seeding and 7 to 8 days in Late-June. Earlier seeding, more longer growth period from emergence to heading they required. 2. Plant height of Pioneer 931 seeded lately was longer than 4.5 meters in primary growth and Sudangrass was about 2.0 to 2.5 meters. Leaf area was the greatest in Mid-August by early seeding but it was increased until Early-October by late seeding. 3. Sorghum gas brought the highest yield in dry mater and Sudangrass the lowest. In general dry matter yield reduced gradually in response to later seeding but Pioneer 931 has brought more than 10 tons per hecter until Late-June. 4. Relative Growth Rate, Leaf Area Ratio and Leaf Weight of all varieties decreased in accordance with growth development. 5. Crude protein content of leaf was higher than stem and the younger the plants, the more protein they contain. Nitrogen Free Extract was just opposite to crude protein.

• Progress in Medical Physics
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• v.17 no.3
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• pp.131-135
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• 2006

A commercial ion chamber matrix was examined the characteristics and its performance for radiotherapy qualify assurance. The device was the I'mRT 2D-MatriXX (Scanditronix-Wellhofer, Schwarzenbruck, Germany). The 2D-MatriXX device consists of a 1020 vented ion chamber array, arranged in $24{\times}24cm^2$ matrix. Each ion chamber has a volume of $0.08cm^3$, spacing of 0.762 cm and minimum sampling time of 20 ms. For the investigation of the characteristics, dose linearity, output factor, short-term reproducibility and dose rate dependency were tested. In the testing of dose linearity. It has shown a good signal linearity within 1% in the range of $1{\sim}800$cGy. Dose rate dependency was found to be lower than 0.4% (Range: 100-600 Mu/min) relative to a dose rate of 300 Mu/min as a reference. Output factors matched very well within 0.5% compared with commissioned beam data using a ionization chamber (CC01, Scanditronix-Wellhofer, Schwarzenbruck, Germany) in the range of field sizes $3{\times}3{\sim}24{\times}24cm^2$. Short-term reproducibility (6 times with a interval of 15 minute) was also shown a good agreement within 0.5%, when the temperature and the pressure were corrected by each time of measurement. in addition, we compared enhanced dynamic wedge (EDW, Varian, Palo Alto, USA) profiles from calculated values in the radiation planning system with those from measurements of the MatriXX. Furthermore, anon-uniform IMRT dose fluence was tested. All the comparison studies have shown good agreements. In this study, the MatriXX was evaluated as a reliable dosimeter, and it could be used as a simplistic and convenient tool for radiotherapy qualify assurance.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.31-39
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• 2016

Background: It is necessary to consider the overall countermeasure for analysis of nuclear activities according to the increase of the nuclear facilities like nuclear power and reprocessing plants in the neighboring countries including China, Taiwan, North Korea, Japan and South Korea. South Korea and comprehensive nuclear-test-ban treaty organization (CTBTO) are now operating the monitoring instruments to detect radionuclides released into the air. It is important to estimate the origin of radionuclides measured using the detection technology as well as the monitoring analysis in aspects of investigation and security of the nuclear activities in neighboring countries. Materials and methods: A three-dimensional forward/backward trajectory model has been developed to estimate the origin of radionuclides for a covert nuclear activity. The developed trajectory model was composed of forward and backward modules to track the particle positions using finite difference method. Results and discussion: A three-dimensional trajectory model was validated using the measured data at Chernobyl accident. The calculated results showed a good agreement by using the high concentration measurements and the locations where was near a release point. The three-dimensional trajectory model had some uncertainty according to the release time, release height and time interval of the trajectory at each release points. An atmospheric dispersion model called long-range accident dose assessment system (LADAS), based on the fields of regards (FOR) technique, was applied to reduce the uncertainties of the trajectory model and to improve the detective technology for estimating the radioisotopes emission area. Conclusion: The detective technology developed in this study can evaluate in release area and origin for covert nuclear activities based on measured radioisotopes at monitoring stations, and it might play critical tool to improve the ability of the nuclear safety field.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.157-164
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• 1992

Changes in the both inward current and conductance of membrane by the fertilization were observed using the one microelectrode voltage clamp(or switch clamp) technique. Unfertilized eggs and both 1- and 2-cell stage eggs after fertilization were donated from the superovulated mouse (ICR, more than 6 weeks old) treated with PMSG(pregnant mare serum gonadotropin, Sigma) and HCG(human chorionic gonadotropin, Sigma) and naturally mated ones, respectively in this experiment. Membrane potential was held at -90mV and the voltage step was applied from -80mV to 50mV with interval of 10mV or 20mV for 300ms. since both of amplitudes and time courses in the membrane currents were various according to the states of cells and clamping condition, results were presented by their $averages{\pm}SEM$(standard mean error)and ratios or percentages. Inward currents began to appear in response to the step depolarization from -60mV and reached its maximum at -50mV. However, since the potential was not clamped evenly during the voltage step, current-voltage(I-V) relationship might be positively shifted 10 or 20mV. From the steady-state currents plotted in the I-V curve, outward rectification was markedly observed. Peak inward currents$(i_{in})$ at -50mV were $-0.62{\pm}0.23nA$(n=4),$-0.52{\pm}0.25nA$(n=5) and $-0.37{\pm}0.25nA$(n=6), in the 1-cell stage, 2-cell stage fertilized eggs and in the unfertilized eggs, respectively. Pure inward current (difference between steady-state and peak, $i_{in. pure}$) were $-1.01{\pm}0.23nA$, $-0.69{\pm}0.43nA$ and $-0.68{\pm}0.29nA$, respectively in the 1-cell stage fertilized eggs, unfertilized eggs and 2-cell stage fertilized eggs. These results suggested that the outward current in fertilized eggs of 2-cell stage was more increased than those in the unfertilized eggs. Pure inward currents in the all stages of eggs showed a similar fashion in the I-V relationship from -50mV to 50mV and reversal potential at 50mV. Time constant of inactivation$({\tau})$ in the inward current was decreased as the membrane potential was depolarized in the unfertilized and 2-cell stage eggs but in the 1-cell stage eggs t was not likely to be affected significantly. Slope conductances were 14.2nS, 8.9n5 and 7.7nS in the 1-cell, 2-cell stage fertilized eggs and the unfertilized eggs, respectively. Membranes between two cells within a zona pellucida seem to be electrical-connected in the 2-cell stage eggs from the observation made in the analysis for the electronic spread and decay to the current stimuli. Both of inward current and membrane conductance were increased after fertilization in the mouse eggs. Inward current seems to be carried by the same ion or through the same channels up to the 2-cell stage and ion that carried inward current was thought to play important function after fertilization in the mouse eggs.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.288-292
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• 1998

Thermooxidative stabilities of soybean oil, beef tallow and palm oil were studied during frying of steamed noodles. Steamed noodles were fried in $150^{\circ}C$ oils for 70 sec at the interval of 30 min. The frying oil was taken every 8 hrs for the analysis of peroxide value (PV) and free fatty acid (FFA) content, fatty acid composition, and tocopherol and tocotrienol content. A little change was shown in PV and FFA content in soybean oil during frying; on the other hand, rapid increase in beef tallow and palm oil was observed. Unsaturated fatty acid content was the highest in soybean oil, followed by palm oil and beef tallow. While fatty acid composition in soybean oil was not changed during frying, unsaturated fatty acid content decreased and saturated fatty acid increased in beef tallow and palm oil, which showed susceptibility to the oxidation. The ratio of linoleic acid to palmitic acid did not show difference with frying time in soybean oil: however, it decreased in other oils with a high correlation with frying time and higher decreasing rate in palm oil was observed. These suggested that soybean oil was the most stable to thermooxidation and the stability was followed by beef tallow and palm oil. Tocopherol was disappeared during frying and 87.5, 81.1, and 73.1% were remained in soybean oil after 8, 16 and 24 hour frying, respectively. Also the rate decreased in the order of ${\gamma}-,\;{\beta}-\;and\;{\alpha}-tocopherol$. However, 34.2 and 169.0 ppm tocopherol and tocotrienol which were present in control samples of beef tallow and palm oil were completely disappeared by 8 hr frying. Therefore, high thermooxidative stability of soybean oil resulted from higher residual amount of tocopherol during frying, and lower stability of palm oil than beef tallow was partly due to high degree of unsaturation.

• Korean Journal of Poultry Science
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• v.15 no.3
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• pp.211-218
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• 1988

Data on egg number from time of first lay to 71 week of age were obtained from samples of single comb white leghorn breeder and brown layer breeder populations which were raised at manny breeding Co. These data were used to estimate the heritabilities of age at sexual maturity, early egg number, residual egg number and annual egg number. Also, the genetic correlation coefficients between these traits were estimated and selection efficiencies of each segment in early part record were estimated by use of the heritabilities and generic correlations. The estimated heritabilities and standard errors in two lines(W and B) were $0.30\pm0.07$ and $0.33\pm0.08$ at early records, $0.19\pm0.06$ and $0.18\pm$0.05 at residual records and $0.37\pm0.09$ and $0.49\pm0.10$ at time of first lay. Those at annual records were $0.24\pm0.06$ equally. The estimated correlation coefficients and standard errors between early record and annual record were $0.76\pm0.08$ and $0.77\pm0.07$. Those between early record and residual record were $0.46\pm0.15$ and $0.39\pm0.16$ respectively. At improving annual egg production per year, selection based on early part record(SM to 40 week of age) would be 69% more efficient than on annual record in line W and 80% more efficient than on annual record in line B. But, if it were considered that egg weight decreased due to sexual maturity and cost for data collection, use of selected segment from 35~40week of age in line W and from 31~40 week of age in line B would be desired in spite of a. small loss in relative selection efficiency. The generation interval would not be shortened.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.236-242
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• 1996

Orostachys japonjcus, called Wasong in herb medicine, has been artificially cultivated as an anti-tumor medicinal. The experiment was done to examine the effect of night-break periods imposed immediately before its bolting time on its morphological, flowering-related characters and fraction dry weights. After a plant was grown in a 15cm plastic pot containing a 2:1 soil:Peat moss mixture for about 3 months, three different night-break periods (0.5, 1 and 2 hours) around midnight were treated from Aug. 24. to compare with the natural daylength. The plants were sampled 6 times by 2-week interval after the treatments. Plant height and inflorescence length of all the treatments inclined with time lapse after the treatment and were shorter in 2 hour night-break due to slow increment than in the other treatments, while stem diameter showed reverse result. All the treatments except 2 hour night -break were nearly same in fraction, shoot and total dry weights per plant; two hour night-break treatment had greater leaf and bract weight from 6 weeks, greater stem, shoot and total weights from 2 weeks and greater root weight from 4 weeks but did less floret weight after the treatment. Although florets on the inflorescence were formed in 2 hour night-break treatment, flowering florets and flowering plants never occurred. In the other treatments showed the similar response, however, more florets appeared from 2 weeks, flowering florets was sharply increased from 6 weeks and flowering plants were reached up to 100% from 6 to 8 weeks after the treatment. Inflorescence length or number of total florets per plant in 2 hour night-break was positive-correlated to all the fraction dry weights except that those of natural daylength was not done, meaning that its artificial cultivation should permit bolting to secure more shoot dry matter.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.4
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• pp.372-380
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• 1996

The operation of Far East Chain(GRI 5970) of Loran - C system had been stopped on June, 1995, but that of Korean Chain(GRI 9930) of Loran - C system which was jointed with North West Pacific Chain(GRI 8930) and Russia Chain(GRI 7950) by international cooperation, was started on January 1996. In this paper, in order to study the accuracy of Loran - C fix of Korean Chain, the authors examined and analyzed the data of the reciever of Loran - C(LC -90, Furuno) and GPS(AccNav Sport super (TM), Eagle) measured automatically and continually for 2 seconds at interval of 5 minutes from November 22, 1992, to January 20, 1996 at the fixed position of National Fisheries University of Pusan, The results obtained were as follows ; 1)The mean time differences of M-W, M-X, and M-Y pair measured in the base observed position were 12333.09${\mu}$s, 28338.44${\mu}$s, and 42806.01${\mu}$s respectively and the mean standard deviations of that were 0.0121${\mu}$s, 0.0290${\mu}$s, and 0.0327${\mu}$s respectively. The daily and monthly variance forms of time difference at each pair appeared in a similar reappearance. 2)The mean standard deviations of the latitude and longitude by Loran - C were 9.1m and 17.4m in W.X pair, 11.5m and 13.7m in W.Y pair, and 8.1m and 29.3m in X.Y pair respectively, and then the probable radiuses within 95% of each pair were 39.2m, 35.7m, and 60.8m, respectively. Therefore, It is to be desired that W.Y par is selected to improve the accuracy in Pusan area. 3)The mean standard deviations of the latitude and longitude by GPS were 15.4m and 15.0m and the probable radius within 95% was 43.4m. 4)The position errors for GPS and each pair of Loran - C were 16.0m to the South in GPS and 265.2m to the East in W.X pair of Loran - C, 279.5m to the North in W.Y pair of that, and 224.3m to the North-West in X.Y pair of that, so GPS is about 250m higher than Loran - C in accuracy.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.1-10
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• 2012

Digital Forecast of the Korea Meteorological Administration (KMA) represents 5 km gridded weather forecast over the Korean Peninsula and the surrounding oceanic regions in Korean territory. Digital Forecast provides 12 weather forecast elements such as three-hour interval temperature, sky condition, wind direction, wind speed, relative humidity, wave height, probability of precipitation, 12 hour accumulated rain and snow, as well as daily minimum and maximum temperatures. These forecast elements are updated every three-hour for the next 48 hours regularly. The objective of this study was to construct Forest Fire Danger Rating Systems on the Korean Peninsula (FFDRS_KORP) based on the daily weather index (DWI) and to improve the accuracy using the digital forecast data. We produced the thematic maps of temperature, humidity, and wind speed over the Korean Peninsula to analyze DWI. To calculate DWI of the Korean Peninsula it was applied forest fire occurrence probability model by logistic regression analysis, i.e. $[1+{\exp}\{-(2.494+(0.004{\times}T_{max})-(0.008{\times}EF))\}]^{-1}$. The result of verification test among the real-time observatory data, digital forecast and RDAPS data showed that predicting values of the digital forecast advanced more than those of RDAPS data. The results of the comparison with the average forest fire danger rating index (sampled at 233 administrative districts) and those with the digital weather showed higher relative accuracy than those with the RDAPS data. The coefficient of determination of forest fire danger rating was shown as $R^2$=0.854. There was a difference of 0.5 between the national mean fire danger rating index (70) with the application of the real-time observatory data and that with the digital forecast (70.5).

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.250-257
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• 1997

Stem diameter and shoot fresh weight of tomato grown in greenhouse were measured non-destructively at 10 minutes interval from 1 to 16 July, 1996 with displacement detector using strain gauges and with suspension-type load cell, respectively, and simultaneously were measured soil water potential, transpiration and solar radiation. Ample water was irrigated before experiment, and thereafter, irrigations were made on the next morning when visual symptoms of wilting appeared. Shoot fresh weight and stem diameter showed very similar patterns in diurnal changes which are characterized by predawn maximum and afternoon minimum and in long- term evolutions, suggesting that stem diameter shrinkage and expansion are closely related to plant water content and growth, respectively, Shoot weight and stem diameter reached minimum values a little later than the time on which transpiration showed maximum. The daily net gains of fresh weight(DG) and stem diameter(DI) showed significantly Positive correlations with solar radiation in those days on which plants were not water-stressed. However, Dl and DG on those days of water stress showed much lower values than expected from the relationships between solar radiation and them. Transpiration was much lower than the expected potential transpiration on 10 July, implying that plants were water-stressed. In this case water stress was not detected from visual symptom of wilting and/or soil water potential, but was able to be identified by the lower DI and DG than the expected. The maximum contraction of stem diameter(MC) and the maximum loss of fresh weight(ML) during daytime showed significantly positive correlations with solar radiation in those days on which plants were not water-stressed and were observed greater than expected from the relationships on severely water-stressed days. But mild water stress could not be discernable by ML and MC. It would be concluded that the daily net gains of fresh weight and/or stem diameter could be used as criteria for diagnosing the water status of tomato and for triggoring the onset of irrigation in automatic system.