• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.195-201
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• 2001

Sowing date experiments were carried out by employing a rice variety "Kwanganbyeo" in both field and phytotron with natural daylength. In phytotron, temperatures were controlled at daily mean of 21$^{\circ}C$ and 24$^{\circ}C$. The responses of final leaf number and beading date were analyzed in relation to daylength during photo-sensitive period (PSP). Based on the component models predicting the final leaf number and leaf appearance rate, a rice phenology model was established and verified. Days from sowing to flowering (DSF) were shortened and final number of leaves (FNL) increased as sowing dates were delayed from 25 April to 5 June in field and phytotron. The increased leaf appearance rate (LAR) and the reduced FNL, respectively, due to the higher temperature and the shorter daylength in delayed sowings in the field brought about greater shortening of DSF than in the phytotron where only FNL was reduced by shorter daylength in delayed sewings. FNL showed very close relationship with the average daylength during PSP of six-leaf stage to panicle initiation, being well fitted to the following rational function ($R^2$=0.98):(equation omitted) where D is daylength and a, b, and c are the constants that were estimated as 14.694, -0.992, and -0.068 in Kwanganbyeo, respectively. The rice phonology model, which was composed of two component models for LAR and FNL, predicted DSF very accurately. The differences between the observed and predicted DSF was less than two days in the sewing date field experiments in 1999 and 2000 of which data were not used for the model construction.struction.

• Journal of the Korean Society of Tobacco Science
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• v.26 no.2 s.52
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• pp.93-101
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• 2004

This study was conducted to investigate the relationship between weather factors during the growing season and chemical components of flue-cured tobacco. Chemical components used in this study was from 'Farm Leaf Tobacco Test' conducted at KT&G Central Research Institute from 1986 through 2003. Data of weather factors during growing season(April to July) were collected in 10 districts measured at Korea Meteorological Adminstration(KMA). Nicotine and total sugar contents, and total sugar to nicotine(TS/Nic.) ratio were increased, whereas total nitrogen to nicotine(TN/Nic.) ratio and chloride content were decreased from 1986 through 2003. Year to year variation of rainfall was the largest, followed by that of sunshine hour. Month to month variation of rainfall also was the largest, followed by that of mean daily air temperature(MDAT). Rainfall was correlated positively with relative humidity(RH), but negatively with sunshine hour. Nicotine content was correlated positively with MDAT(in July, June$\~$July, May$\~$July and average), but negatively with rainfall(in May$\~$July) and with RH(in June, July, May $\~$June, June $\~$July, April$\~$June, May $\~$July and average). Total sugar content was correlated positively with MDAT(in May), but negatively with sunshine hour(average) and RH(in June, July, June$\~$July, April$\~$June, May$\~$July and average). The positive correlation was found between total nitrogen content and sunshine hour(in April, May, April$\~$May, May$\~$July, April$\~$June and average). The negative correlation was found between TS/Nic. ratio and sunshine hour(in May$\~$July and average). TN/Nic. ratio was correlated positively with sunshine hour(in May and April$\~$May) and with RH(in July and June$\~$July), but negatively with MDAT(in July, June$\~$July, May$\~$July and average). Ether extraction content was correlated positively with MDAT(in July, June$\~$July, May$\~$July and average) and with sunshine hour(in July and June$\~$July), but negatively with rainfall(in April, July, May­July and average). Chloride content was correlated positively with sunshine hour(in April, July, April$\~$May, June$\~$July, April$\~$June, May$\~$July and average), but negatively with rainfall(in April, April$\~$June and average).

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.45-49
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• 2011

This research was carried out to investigate frost damage of mulberry tree (Morus alba) according to topographic characteristics in Buan province. The first bud-break, leafing, blooming and harvest date of mulberry tree in 2010 were two, four, fourteen and eight days later than those in 2009, respectively. These results were that daily mean temperature during March and April in 2010 were lower than those in 2009 by $2.3^{\circ}C$ and $2.4^{\circ}C$. Frost damage of orchards at flat-bottomed valley, flat near hill and lake, and plain were 50.0%,12.0%, and 4.2%, respectively. Also, frost damage of branch of below 15 mm in diameter was serious than that of branch over 16 mm, but orchard at flat-bottomed valley was high as the range of 46.2~54.0%. These results in 2010 were caused by occurrence of below zero temperatures in leafing stage. Since then, many shoots came out at accessary bud on proximal and the top part of the branches. Therefore, frost damage of mulberry tree in Buan province in 2010 was caused by occurrence of below zero temperatures on April and topographic characteristics of orchard.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.461-467
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• 1992

A mungbean cultivar, 'Seonhwanogdu', was seeded on April 20, May 10, June 1, June 20, July 10 and July 30 in 1988, 1989 and 1990 to determine the optimum seeding date of mungbean in Cheju province. As seeding was delayed from April 20 to June 20, the number of days from emergence to first flowering (days to flowering) decreased from 56.7 to 36.7 days, on the three year average. Days to flowering of mungbean seeded on July 10 and 30 ranged 30 to 35 days except that of the plants seeded on July 10, 1988. Days to flowering linearly decreased as the average of daily mean air temperature from emergence to the first flowering increased. The number of days from the first flowering to the first maturity (days to maturity) in mungbean seeded on April 20 to July 10 ranged 14 to 21 days and was 29 to 40 days at the July 30 seeding. The number of pods per plant, the number of seeds per pod, 1000 seed weight and yield tended to increase with delaying seeding up to June 1 and June 20, and then to decrease with further delaying seeding. This study indicates that the optimum seeding time of mungbean in Cheju province is around mid-June.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.105-110
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• 2011

This study determined the effects of the dietary moisture level and feeding rate on the growth and gastric evacuation of young olive flounder. Four experimental diets with different moisture levels (9%, 21%, 30%, and 40%) were prepared through the addition of water to the commercial extruded pellet. Three replicate groups of fish (initial weight: $106{\pm}1.4\;g$) were fed diets containing 9%, 21%, 30%, and 40% moisture to satiation or a moisture level of 9% and 30% at a restricted feeding rate (95% of satiation) for 15 weeks. The mean water temperature was $22{\pm}1.6^{\circ}C$ during the feeding trial. Gastric evacuation rates were determined post-feeding. The dietary moisture levels did not significantly affect weight gain, but the weight of the fish receiving 9% and 30% moisture diets to 95% satiation were significantly lower than those of the fish fed 9-40% moisture diets to 100% satiation (P<0.05). The feed efficiency, protein efficiency ratio, viscerosomatic index, and survival were not significantly affected by the dietary moisture levels and feeding rates. The daily feed intake of the fish fed to 100% satiation did not significantly differ among the treatment groups. The stomach contents that peaked within 3 h of feeding gradually decreased, and the stomachs of fish were completely evacuated within 18 h. The contents of the intestine peaked at 3-12 h post-feeding, and then declined with the intestine being mostly evacuated at 30 h. The moisture of the stomach contents reached approximately 70% within 3 h post-feeding and gradually increased to approximately 75% within 12 h. No considerable differences were observed in the gastric evacuation and moisture levels of the stomach contents in the fish fed the different diets. The results of this study suggest that the gastric evacuation of olive flounder was not affected by the dietary moisture level and that the addition of water into the diet displayed no beneficial effects on the growth of young olive flounder.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.5
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• pp.749-754
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• 2017

Objective: The objective of the present study was to investigate the effects of farrowing month (FM), parity and sex on the growth performance of Berkshire swine raised in alternative production systems. Methods: A total of 40 farrowing records from 27 sows and 1,258 body weight (BW) records from 274 piglets collected over a two-year period were used for the analysis. The BWs were recorded at birth, weaning (28 d), 56, 84, 112, and 140 days. Any BW not recorded on schedule was recalculated to conform the days of age among corresponding BW records, using growth curves drawn with polynomial functions whose power was determined by the number of existing observations for each individual. Results: The mean parity (${\pm}$standard deviation) of the sows was $3.42{\pm}2.14$. The sows that farrowed in June had the lowest number of total born with an average of $6.25{\pm}2.22$ piglets per sow. However, the lowest average number of piglets weaned at day 28 was found in sows that farrowed in May, as well as the highest number recorded for the stillborn piglets with an average of 2.67 piglets per sow. Moreover, the smallest increase in weight from birth to weaning occurred in piglets that were farrowed in May, which also corresponds with the average daily gain (ADG) of 0.29 kg and the last recorded weight measurement on day 140 of $41.69{\pm}1.45kg$. Contrastingly, the highest growth rate was found among pigs farrowed in June, with the largest increase in weight of 7.55 kg from birth to weaning, the highest ADG of 0.51 kg from birth to 140 day of age and the highest BW of $74.70{\pm}1.86kg$ recorded on day 140. Conclusion: Pigs farrowed in June also had the least number of piglets that died between birth and weaning. The zone of thermal comfort found in sows reared in indoor confinement systems did not improve the reproductive performance of the sows reared in an outdoor, alternative production system, while the growth performance of the piglets was improved when the ambient temperature was consistently hot or consistently cold.

• Journal of Conservation Science
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• v.27 no.4
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• pp.381-393
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• 2011

This study focus on the surface deterioration diagnosis based on the material characteristics of Taean Dongmunri Maaesamjonbulipsang(rock-carved standing triad Buddha Statue) and the weathering environment analysis. Rock materials of the triad Buddha is coarse-grained biotite granite which is composed mainly of quartz, K-feldspar, plagioclase, biotite and muscovite. The triad Buddha was serious surface irregularity(13.5%), exfoliation(12.3%) and discoloration(46.6%), and the physical characteristics using ultrasonic velocity appeared fourth grade (0.59, highly weathered). Korean style wooden shelter of the triad Buddha(closed type) maintained high humidity environment (daily mean; 86.6%) than exterior environment, and appeared the possibility of deterioration by freezing-thawing because the temperature showed below zero temperatures in winter. The shelter was changed from closed-type to open-type to relieve the moisture problem recently. But the moisture problem is yet to be solved because surface water flowing along northern wayside is flowed into triad Buddha. Therefore, environmental control will need to stop inflow of water into triad Buddha.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.115-125
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• 2001

To examine the movement of the freshwater discharged artificially into the estuary during ebbing period in the Keum River dike we observed surface salinity variations in three stations along the estuary channel in May 1998 and July 1997 and surface temperature and salinity along the ferry-route between Kunsan and Changhang during eighteen days in July 1999. Based upon the typical features of observed salinity variation, we analyzed the excursion and decay processes of the discharged water. When freshwater is discharged, the low-salinity water forms strong salinity front over the entire estuary width, which basically moves forth and back by tidal modulation along the channel, producing the sudden change of surface salinity with the front passage. Salinity distribution along the channel, which is deduced from time variation of mean salinity over the estuary width, after one tidal period from gate operation suggests that diluted low-salinity water is trapped to the front and surface salinity increases gradually toward the upstream region. This frontal distribution of salinity is interpreted to be produced by the sudden gate operation supplying and stopping of freshwater within about two hours. Daily repeat of freshwater discharge produces separation (double front) or merge between decaying and new-generated fronts depending on dike-gate opening time, and the front decays with salinity increasing if the freshwater supply is stopped more than two days. In addition, the observed fluctuations and deviations in surface salinity variation is explained in terms of the differences of fronts intensity, their transition time and temporal salinity front running along the channel, which can be generated due to artificial gate-operation for the discharging time and water volume in the estuary dike.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.642-652
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• 2006

In order to understand the characteristics of surface ozone concentration and high $O_3$ concentration days, regional data from seven air quality monitoring stations which were operated by local governments were analyzed Regional characteristics of $O_3$ concentration were analyzed with the data of $O_3$ concentration and the characteristics of $O_3$ generation and weather conditions by the selection of the days in which the concentration was higher than 80 ppb. In the case of daily variation, the lowest $O_3$ concentration was shown in all regions from 7am to 8am and the highest around at 4 pm. The monthly variation of mean $O_3$ concentration and ${\Delta}O_3$ values revealed a reducing pattern in July and August following the peak in June, and again a gradual increasing trend in September and October. The result shows that the amount of ozone is dependent on photochemical reaction. The days of $O_3$ generated more than 80 ppb in the region of Gwangyang-bay were 544 days(1,760 hrs). The frequency of occurrence in the region revealed a strong pattern with the order of Samil-dong, Jinsang, and Gwangmu-dong stations in the Gwangyang region. However, Tein-dong, which is the nearest station to air pollution material generation source, showed the lowest frequency in the study area. Consequently, the meteorological parameters which can easily generate the high concentration of $O_3$ in the region of Gwangyang-bay are characterized as follows; atmospheric temperature which is higher than $19^{\circ}C$, relative humidity with the range of $60{\sim}85%$, the less average wind velocity than 5 m/s, cloud cover which is less than 5/10, and the more duration of sunshine than 8 hours.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.229-237
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• 2019

This study was conducted to estimate annual reference evapotranspiration (ET₀) for the agro-climatic zones for rice paddy fields in South Korea between 1980 and 2015. The daily ET₀ was estimated by applying the Penman-Monteith method to meteorological data from 61 weather stations provided by Korean Meteorological Administration (KMA). The average of annual ET₀ from 1980 to 2015 was 1334.1±33.89 mm. The ET₀ was the highest at the Southern Coastal Zone due to their higher air temperature and lower relative humidity. The ET₀ had significantly increased with 2.81 mm/yr for the whole zones over 36 years. However, the change rate of it was different among agro-climatic zones. The annual ET₀ highly increased in central zones and eastern coastal zones. In terms of correlation coefficient, the temporal change of the annual ET₀ was closely related to variations of four meteorological factors (i.e., mean, minimum temperatures, sunshine duration, and relative humidity). The results demonstrated that whole Korean agro-climatic zones have been undergoing a significant change in the annual ET₀ for the last 36 years. Understanding the spatial pattern and the long-term variation of the annual ET₀ associated with global warming would be useful to improve crop and water resource managements at each agro-climatic zone of South Korea.