• Journal of the Korean earth science society
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• v.41 no.5
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• pp.459-468
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• 2020

In this study, the selection criteria for the occurrence of sea breezes in the Boseong area during the spring season (March-May) of 2016-2017 were prepared for the analysis of vertical weather characteristics. For this purpose, wind speed values were determined using the measured precipitation, cloud volume, wind direction, the difference between the ground and sea temperature, a wind Profiler at an altitude of 1 km, and numerical model data. The dates of the sea breezes in Boseong were classified according to the selection criteria, and the spatial and temporal characteristics of the sea breezes were identified by analyzing the time and altitude of the sea breeze and the size of the wind speed. Sea breezes occurred 23 out of 183 days (12%), and in Boseong, at least 1.2 out of 10 spring days exhibited sea breezes. Sea winds ranged from 1200 to 1800 LST, mainly from ground to 700 m altitude during the day. In addition, the maximum wind speed averaged 4.9 m s^-1, at an altitude of 40 m at 1600 LST, showing relatively lower values than those in a preceding study. This seems to be owing to the reduction in wind speed due to the complexity of the coastal terrain.

• Journal of Life Science
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• v.30 no.10
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• pp.844-850
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• 2020

Disaster-related extreme weather is rapidly increasing due to climate change. In Korea, typhoons accompanied by rainfall usually approach in August and September, causing great damage. The purpose of this study is to find a gene that regulates the heading date of rice in order to avoid loss of harvest from climate change and typhoons. Cheongcheong/Nagdong doubled haploid (CNDH) was used as the plant material to investigate the location of heading-related genes using QTL and sequence analysis by cloning the gene. In the distribution chart, the heading dates, culm lengths, panicle lengths, numbers of panicles, and 1,000-grain weights all have normal distributions. QTL analysis found 13 contigs on chromosome 8. One QTL, named qHd8, was detected on chromosome 8. The range at qHd8 was approximately 7.7 cM, with RM72 and RM404 markers near the peak. There were 13 contigs and 1 ORF. Protein sequence analysis showed that rice was similar to Os08g0341700, AtSFH13, and AtSFH7 proteins. Os08g0341700, which is involved in signal transduction, is similar to phosphatidylinositol transfer-like protein II, and complete information is not available, but it is believed to play a role in the phosphatidylinositol-specific signaling pathway related to Sec14P.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.424-432
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• 2005

Newly introduced two lines of apios (Apios americana Medikus, red-vine and green-vine) were grown in Jeju island, to clarify their growth and production characteristics as well as to develope as a new edible crops in Korea. Both lines bloomed but did not develop to pod and seed. The red-viny line showed the habit of more early growth and maturity compared with green-viny line. Fresh tuber yields per 10a harvested in late November ranged from about 500kg to 800kg as according to the lines and cultural condition. Fresh tuber yield of red-viny line was relatively greater than that of green-viny line, mainly due to their higher tuber number per plant. Among the planting dates(April 1, April 16 and May 1) of seed tubes, highest tuber yield was obtained on May 16 planting. And the stacking cultivation culture was better than non-stacking cultivation in respect of tuber yield and disease avoidance. These results indicate that apios can produce in Jeju island, and in order to extend its cultivation to farmers it will be needed to develope some cultivars with high yields as well as labor-saving cultivation methods.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.327-327
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• 2017

The effect of different seedling ages and transplanting times on the growth and yield of Indica ${\times}$ Japonica rice for noodle processing was evaluated to develop a high yielding cultivation technology for increasing the competition against the imported foreign rice. Four seedling ages (10-, 20-, 30- and 33-day old) of two Indica ${\times}$ Japonica rice cultivars (cvs. Saemimyeon and Palbangmi) and three transplanting dates (May 20, May 30 and June 9) were used in the study. Our results showed that the growth and rice yield of the two cultivars were significantly affected by the different seedling ages and transplanting times. Dry matter production at the panicle heading of the two rice cultivars were generally higher in the 30-day old seedling than the other seedling age treatments and then gradually decreased as the transplanting time was delayed from May 20 to June 9. Similar high panicle number per square meter were recorded at the 30-day old seedling between May 20-May 30 transplanting times. In contrast, other yield parameters that includes spikelet number per panicle, 1,000-brown rice weight, and ripened grain ratio (except for the June 9 transplanting time of Palbangmi) were not significantly affected. The milled rice yield of Saemimyeon was higher than that of the Palbangmi regardless of seedling ages and it was also the highest at the 30-day old seedling with four seedling ages. The milled rice yield of Saemimyeon was only slightly decreased as the transplanting time was delayed from the May 20 to June 9 but Palbangmi had a significantly lower milled rice yield at June 9 transplanting due to the low ripened grain ratio. The result indicates that the most suitable seedling age for the cultivars tested was at 30-day old seedling for noodle processing rice and recommended transplanting times were between May 20 and May 30 for the high rice yield in the Yeongnam plain area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.137-143
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• 2012

This study was conducted to investigate the yield and greenness of "Nogwonchalbyeo" on the basis of different date of transplanting and harvesting. Delay in heading was observed in the plants transplanted later but no effect on heading was observed due to different levels of nitrogen fertilizer. Percentage of green color in dehusked rice was higher in the grains of rice transplanted on 10th June. An increasing trend was observed in the yield with the delay in the date of transplanting, maximum yield was observed in the rice planted on 10th June but a decrease in yield was recorded if transplanted after 15th June. Similarly, yield also increase as the days for harvesting increased until 37 days after heading but beyond 37 days decreasing trend was observed in yield. Based on the above findings it can be suggested that 4~6 June and 9kg/10a are the optimum dates of transplanting and amount of nitrogen while 3 5~37 days after heading is the best time for harvesting of "Nogwonchalbyeo".

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.204-210
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• 2006

The purple color in flesh of 'Jasim' potato (Solanum tuberosum L.) tubers is due to an accumulation of anthocyanin. The experiment was conducted to determine what is the key factor among cultural environments that affect the accumulation of anthocyanin in 'Jasim' potato tubers, and the effect of nitrogen fertilization levels on that. Through analysis of anthocyanin content of purple-fleshed tubers produced under the different cultural environments of three localities and two planting dates, we determined that lower temperature during 30days before harvesting resulted in higher anthocyanin accumulation of 'Jasim' potato tubers. In the experiment of different level of nitrogen fertilization, 'Jasim' potato tubers produced in highland (Daegualryeong) showed higher content of anthocyanin in the treatment of recommended level than in treatment of lower or higher level as compared with the recommended level. However, significant difference of anthocyanin content among different nitrogen fertilization levels was not observed in lowland (Gangnung). These results suggest that the selection of locality or cropping system and the optimal fertilization management are very important factors for production of higher pigmented tubers in purple-fleshed potato.

• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.418-435
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• 2001

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.179-188
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• 2012

A kiwifruit cultivar 'Hayward' has been grown in Jeju Island where the current climate is suitable for growth and development of this crop. Prediction of the geographical shift in the phenology can help the kiwifruits growers to adapt to the local climate change in the future. Two phenology models (i.e., chill-day and DVS) were parameterized to estimate flowering date of kiwifruits 'Hayward' based on the data collected from field plots and chamber experiments in the southern coastal and island locations in South Korea. Spatio-temporally independent datasets were used to evaluate performance of the two models in predicting flowering date of 'Hayward'. Chill-day model showed better performance than DVS model (2.5 vs. 4.0 days in RMSE). Daily temperature data interpolated at a higher spatial resolution over Jeju Island were used to predict flowering dates of 'Hayward' in 2021-2100 under the A1B scenario. According to the model calculation under the future climate condition, the flowering of kiwifruits shall accelerate and the area with poor flowering might increase due to the warmer winter induced insufficient chilling. Optimal land area for growing 'Hayward' could increase for a while in the near future (2021-2030), whereas such areas could decrease to one half of the current areas by 2100. The geographic locations suitable for 'Hayward' cultivation would migrate from the current coastal area to the elevated mountain area by 250 m.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.573-580
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• 2006

A sediment core from the Cheollipo arboretum ($36^{\circ}$ 47' 57'N, $126^{\circ}$ 09' 04') was studied for pollen analysis in order to reconstruct postglacial vegetational change and environmental changes around the central western region of the Korean Peninsula. The record shows four pollen assemblage zones: Zone CHL-I, Quercus stage (ca. 9,300$\sim$6,200 yr BP): zone CHL-II, Quercus-Pinus stage (ca. 6,200$\sim$4,600 yr BP); zone CHL- III, Pinus-Quercus stage (ca. 4,600$\sim$1,160 yr BP): zone CHL-IV and Pinus stage (ca. 1,160 yr BP-present). During the 9,300$\sim$8,500 yr BP, the early Holocene, researchers have guessed a piece of cool-temperate norihern/altimontane mixed coniferous and deciduous broad-leaved forest. Between 8,500$\sim$4,600 yr BP the Quercus dominated the landscape of study area and the established dates of this typical cool-temperate central/montane deciduous broad-leaved forest vegetation might be ca. 6500 yr BP, and then the Pinus developed around the site at ca. 5,700 yr BP. The abrupt increase of Pinus and NAP (non-arboreal pollen) after ca. 1,100 yr BP indicates the vegetation changes due to human activities. From the dynamics of the Chenopodiaceae pollen indicating salt marsh and freshwater pollen flora such as Typha, Trapa, Nymphoides and so forth, we suggest that the tidal flat was altered into freshwater lake around 6,500 yr BP.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.125-136
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• 1981

This experiment was conducted to study the influence of different cultivation periods on some morphological and agronomic characteristics of rice plant at Iri, the Honam plain, in 1979. Early maturing varieties showed little delay in heading with late transplanting, but intermediate and late maturing varieties showed more than 7 day delay in heading. The number of days required to reach heading was over 55 and 67 days after transplanting in early and intermediate-late maturing varieties, respectively. There was significantly postitive correlation between the length of vegetative stage and the grain yield. The mean temperature during ripening period was significantly correlated with the grain yield and the percentage of filled grains. The length, width, and thickness of leaf increased with earlier transplanting and the elongation degree between upper and lower leaves showed the same tendency. The productivity of dry matter and the translocation rate of photosynthate to spikelet decreased with late transplanting mainly due to low temperature. LAI was also influenced by transplanting date showing close correlation with yield. Early transplanting was desirable for assimilation and dry matter accumulation.