• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.1-9
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• 1980

To determine the optimum harvest time of recent rice varieties from Indica/Japonica remote crosses, leading varieties Suweon 264 and Milyang 23 were tested for the changes in dry matter weight and moisture content of grain, shattering, shelling ratio, milling ratio, and apparant physical quality during grain development at 5 day-intervals from 20 days to 55 days after heading. The results are summarized as follows: 1. Grain weight (dry matter) reached its maximum (physiological maturity) at 30 days after flowering (DAF) in Suweon 264, and at 35 days in Milyang 23, and thereafter it did not change significantly until 55 DAF. 2. Time course of decrease in grain moisture content (Y, %) during maturation (X, DAF) consisted of two linear phases, i.e. a fast and a slow period: Y=68.245-1.33X until 34DAF, and Y=23.025-0.470X until 55DAF after 34DAF in Suweon 264; Y=73.62-1.634X until 24.5DAF, and Y=33.59-0.570X until 55DAF after 24.5DAF in Milyang 23. Two varieties showed the same grain moisture content of 28% (wet basis) at physiological maturity in spite of the distinct differences in the heading date, time of physiological maturity and thereby ripening climate. 3. Force to shatter a grain ranged about 90 to 100g in Milyang 23, and about 200 to 250g in Suweon 264 and in a Japonica variety, Jinheung. The force, however, did not change significantly with harvest time from 35DAF to 50DAF. 4. The changes in the ratios of shelling, milling, broken rice and tinted rice with harvest time were insignificant during a period from 35DAF to 55DAF. However, ratios of green rice and white belly rice decreased significantly with delay in harvest time during 10 days after physiological maturity. 5. The best time of harvest for maximum yield and good quality is thought to be 10 days after physiological maturity, and grain moisture content at this time was about 20% on wet basis.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.133-137
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• 2011

In this study, illite was size-reduced using a wet-ball-milling treatment to improve its dispersion. Changes in illite particle size, size distribution, and dispersion characteristics after varying the treatment period were investigated. And the dispersion and dispersion stability of illite solution after 2 h wet ball milling treatment with different pH conditions were also evaluated. The illite particle size significantly decreased as the treatment time increased and the size reduction effect of wet ball milling deteriorated above 2 h treatment time. In addition, illite particle size was more evenly distributed as the treatment time increased. X-ray diffraction (XRD) analysis showed that no crystal structural changes of illite were induced, but the characteristic peak of illite the weaker due to the size reduction and exfoliation, as the treatment time increased. Zeta potential analysis showed that the illite dispersion improved, as the treatment time increased. The illite wet-ball-mill treated at pH 2 had the lowest dispersion stability. Illite dispersion and dispersion stability increased as pH increased, due to the increase in surface ionization. Hence, the results showed that as the treatment time increased, the illite particle size decreased, and dispersion and dispersion stability improved due to the increase in surface energy and repulsion force between particles.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.69-73
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• 2007

Inorganic geochemical and mineralogical analyses from the trench sediments of the Hwayang wetland were carried out to verify the wet/dry conditions during 6000 - 5000 yr BP and abnormal event of 6300 yr BP of Korean west coast. Lithostratigraphy, mineralogy and major element concentrations of the sediments of the trench indicate that during 6000 - 5000 yr BP, a wet/dry conditions might be repeated at an interval of 200 years. Carbonate minerals precipitated with the decrease of water depth in the lake or wetland after about 6000 yr BP. On the other hand, the sediments coarser in mean grain size and larger in standard deviation were corresponded with periods of 6300 yr BP and 6230 yr BP. Especially, such a feature of grain size distribution of 6300 yr BP appears in other wetlands situated in the west coast, e.g., Hwangsan wetland and Cheollipo coastal wetland. During the period, the coarse sediments seem to have been delivered by a high energy like storming.

• Journal of the Korean association of regional geographers
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• v.18 no.4
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• pp.364-373
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• 2012

This study is to analyze distribution and change of montane meadows on the lava plateau in the east face of Mt. Baekdu. Process for aims carried out field survey, and analyzed landsat images of 1993, 1999, 2004, and year 2010. After research findings, the area of forests has increased by 33% from $636km^2$ to $848km^2$, montane meadow has decreased by 58% from $303km^2$ to $127km^2$ during 18 years. Montane meadows could be classified as 2 categories of wet meadow and dry meadow by the geomorphic environments and vegetation types. Wet meadow has decreased by 30%, dry meadow has decreased by 70% in the same period. Decreasing areas are replacing meadows with forests in invasion by trees and shrubs. According to the analysis with weather data for 16 years from 1993 to 2008, temperature has increased by $1.6^{\circ}C$, on the other hand, precipitation has decreased by 5.3mm. These kinds of climate change trends continue in the future, it could be change montane meadows into tree types.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1425-1434
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• 2008

The study was conducted to evaluate and compare the effects of feed additives on ruminal fermentation, nutrient digestibility and performance of lambs fed diets containing 60% wet brewers grains (WBG). In Experiment 1, two simultaneous trials were conducted. Fifty intact ($20.2{\pm}0.8kg\;BW$) lambs were used in a feedlot trial and 10 (rumen cannulated; $32{\pm}1kg\;BW$) in a digestion trial. The pH, volatile fatty acids (VFA) and ammonia-N in lambs were also estimated. Lambs were randomly assigned to one of five diets: i) without additives (Con), ii) with 1% bicarbonate (Bic), iii) with 1% bentonite (Ben), iv) with 33 mg/kg monensin (Mon) and v) with 200 mg/kg fibrolityc enzymes (Enz). In Experiment 2, 120 RambouilletPelibuey intact male lambs ($19.5{\pm}1.5kg\;BW$) were used in a feedlot trial and randomly assigned to four diets: i) without additives (control), ii) with 1% Bic, iii) with 33 mg/kg Mon and iv) with 1% Bic and 33 mg/kg Mon. In Experiment 1, lambs fed diets containing Bic or Mon had significantly higher final weight, DMI, ADG than other lambs. However, apparent DM, OM, CP, NDF and ADF digestibilities and ruminal individual VFA content were similar (p>0.05) among treatments. Conversely, treatmentcollection period interaction was significant for ruminal pH and NH3. In Experiment 2, lambs fed diets containing a Bic and Mon combination had significantly higher final weight, DMI and ADG. It is concluded lambs fed Bic or Mon or Bic and Mon combination had better performance characteristics than lambs on Ben or Enz.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.491-495
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• 2001

The behaviour of 5 Jersey and 5 Guernsey heifers, grazing on natural vegetation in a sub-humid tropical environment in Kenya, was studied during the dry (January and February) and wet (April and May) seasons in 1999. The heifers grazed for 12 hours daily in both seasons. Observations on feeding, standing, lying and ruminating were done chronometrically, at five-minute intervals, between 0600 and 1800 h. During the dry season, the average feeding, standing, lying and ruminating times per 12 h period for Jerseys was 8.0, 3.13, 0.87, and 1.40 respectively, while those for Guernseys were 8.6, 3.26, 0.4, and 1.35 respectively. In the wet (green) season, the mean feeding, standing, lying and ruminating times for Jerseys were found to be 7.54, 3.07, 1.39, and 1.27 respectively, and for Guernseys were 8.42, 3.10, 0.48, and 0.44 respectively. In both seasons Guernseys spent more time feeding (p<0.05) in comparison with the Jerseys. It was also observed that lying occurred more often in Jerseys than the Guernseys (p<0.05) in both seasons. During the wet season, Jerseys ruminated longer (p<0.05) than the Guernseys. The health status of the animals was determined by examining the respiratory frequency, heart rate, rectal temperature, haemoglobin erythrocytes and leucocytes of the experimental animals. All the clinical and physiological parameters were within the normal physiological range of healthy cattle. It was concluded that there are differences in grazing behaviour between Jerseys and Guernseys in the sub-humid tropical environment of Kenya and Jerseys seem to be more adapted to the tropical climatic conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.832-840
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• 2014

This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures ($5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$) and four durations (0, 1, 2, and 3 d) were arranged in a $4{\times}4$ factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as $25^{\circ}C$ and $35^{\circ}C$. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds $35^{\circ}C$, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above $35^{\circ}C$ during summer.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.235-246
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• 2012

Typhoon induced surge simulations are done to make an establishment of coastal disaster prevention plan. To apply efficient run-up and overtopping on vertical harbor docks, in which prevailing wet-dry scheme cannot be satisfied due to infinite steepness, an imaginary internal barrier concept introduced and analyzed. Before real application on the Mokpo harbor area, feasibility tests are done on an idealized simple geometry and as a result it is found that the moderate width of the barrier might be 1 m. The threshold value of the minimum wet depth $H_{min}$ for land area, which behaves sensitive role in inundation area and depth, depends on grid size. However it is revealed that 0.01 m is adequate value in this fine finite element with 10 m spacing. A hypothetical typhoon of 100 years return period in central pressure and maximum velocity is generated based on historical tracks. Simulation of possible inundation on Mokpo area is performed with asymmetrical vortex of hypothetical typhoon and wave coupling. Model results show general agreement in pattern compared to other's prediction, however possibility of inundation enlargement is expected in harbor area.

• Korean Journal of Plant Resources
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• v.29 no.3
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• pp.339-346
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• 2016

This study was carried out to develop an effective seed propagation method for Thalictrum rochebrunianum var. grandisepalum (H. Lev.) Nakai by analyzing seed dormancy types and germination characteristics. Seeds were collected between September to October at Gangwon province, and well-selected seeds were used while being dry-stored at 4±1℃. The seed size ranged 4.52 × 1.58 ㎜ and the weight of thousand seeds were 1,603.5 ± 0.02 ㎎. The moisture content was 7.2%. Seeds were achene type, and morphology characters showed an elliptical shape and rough texture, and light brown in color. Moist-chilling treatment was conducted for dormancy breaking because the seeds had an undeveloped embryo of liner type. The embryo had developed during a moist-chilling period, constantly, and fully developed in 10 weeks. Consequently, it seemed to be non-deep complex or intermediate complex type of morphophysiological dormancy, and embryo dormancy was broken by wet-chilling for 10 weeks. After 10 weeks of wet-chilling treatment, seed germination began. Germination percentage was higher in dark condition raher than light condition and recorded the maximum at 25℃ in the dark (16.3%). A pre-soaking treatment with a combined plant growth hormones promoted germination and shortened T₅₀. Specifically, seed germination of 84.5% was achieved by pre-soaking of seeds with a combined solution of 500 ㎎/L GA₃ and 10 ㎎/L kinetin for 24 h after a wet-chilling treatment for 10 weeks. Thus the effect of plant growth hormones coupled with chilling temperature on seed breaking dormancy provide asubsequent growth of seedlings for successful plantation.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.154-154
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• 2022

The frequency of natural disasters, including floods and drought events, driven by climate change has increased in recent times. Investigating the climate regimes and the roles of climate variables are indispensable to forestall future climate change-related disasters. This study compares the variability of two popular and widely used climate indices i.e., the United Nations Environment Programme (UNEP) aridity index and the Modified De-Martonne (MDM) index to assess the trend of climate change in the Chungcheong provinces of South Korea. The trend of annual and monthly climate indices was conducted using a non-parametric Mann-Kendall test and Kolmogorov-Smirnov normality test with daily climate data of 48 years (1978-2020) from 10 synoptic stations. The findings indicate that UNEP and MDM indices had a wet climate regime for the annual trend, with the UNEP index indicating a relatively humid trend of 60% humid, 20% semi-arid, and 10% sub-humid for the 48-years study period. However, the MDM index showed a high frequency of a severe wet climatic condition followed by the semi-arid condition. The months of July and August had the highest occurring frequency of the wet climatic condition (90%) for both UNEP and MDM indices. Comparing the two provinces, Chungnam showed a relatively wetter climatic condition using the UNEP index, while the MDM index indicated no significant regional difference in climate regime between the two provinces. The Kolmogorov-Smirnov normality test showed that all the 10 stations are normally distributed for monthly climate conditions at a 5% significant level in the two provinces except five stations for UNEP index and four stations for MDM index in the month of January.