• Korean Journal of Plant Resources
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• v.33 no.1
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• pp.1-14
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• 2020

This study was conducted to analyze community structure and species composition of Pinus densiflora for. erecta Stand in Mt. Cheonchuk (653 m). Field survey was carried out from June to September in 2013. 74 plots (20×20 m) were set up, 5 herb layer plots (3×3 m) were constructed for each plot, and there, Diameter at Breast Heigh t(DBH), height, environmental factor, annual growth were measured. Vascular plants were surveyed as following; 66 family, 165 genus, 211 species, 2 sub species, 29 variety, 6 form 248 taxa. Results of cluster analysis for P. densiflora for. erecta forest, 3 communities were divided into; Quercus mongolica (P-1), Quercus variabilis (P-2) and Quercus aliena-Stephanandra incisa (P-3). There were significant environmental factors that organic layer, annual growth, CEC, total total nitrogen, organic matter and pH for each community. As a result of DCA, P-1 and P-2 were distributed large range of environmental factors but relatively limited in P-3. Distributions of herb layer were affected by sand, cation exchange capacity, silt and total nitrogen. Results of MRPP test for herb layer communities, it was significantly analyzed (A=0.003, P<0.008). Species diversity index was highly recorded in P-3 and influenced by cation exchange capacity, total nitrogen, annual growth in consequence of NMS analysis.

• Journal of the Korea Concrete Institute
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• v.19 no.2
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• pp.189-197
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• 2007

Concrete tunnel lining must be designed to having the fireproof performance because the lining are sometimes exposed to very high temperature due to traffic accident. Such fire temperature may cause explosion of concrete, or collapse of tunnel structure. The purpose of this study is to obtain the fundamental fireproof behavior of fire resistance-engineered cementitious composites(FR-ECC) under fire temperature in order to use the fire protection material in tunnel lining system. The present study conducted the experiment to simulate fire temperature by employing 2 types of FR-ECC and investigated experimentally the explosion and cracks in heated surface of these FR-ECC. Employed temperature curve were hydro carbon(HC, ECl) criterion, which are severe in various criterion of fire temperature. The numerical analysis is carried out the nonlinear transient heat flow analysis and verified against the experimental data. The complex features of behavior in fire conditions, such as thermal expansion, plasticity, cracking or crushing, and material properties changing with temperature are considered. By the use of analytical model, the concrete tunnel subjected to fire loads were analyzed and discussed. With comparison of current concrete materials and FR-ECC, the experimental and analytical results of FR-ECC shows the better fire resistance performance than the other.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.78-85
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• 1987

In order for Paldanghomil (winter rye) to be investigated if its grain yield is able to be produced after clipping just before winter season for forage utilization this experiment was carried out under the four sowing dates of four locations in Korea (Chunchon, Suwon, Hwasung and Chungju). In rye clipping plot earlier sowing showed taller plant height, more number of tillers/㎡ and higher forage yield before winter season, indicating the highest forage yield (1803 kg/10a) in Chunchon by sowing of September II. Forage yield of rye before winter season was mainly influenced by plant height and number of tillers/㎡, showing more effect of plant height. Rye plants were more or less affected on winter damages, late heading and short culm by clipping before winter season. Analysis of variance indicated that only number of spikes/㎡ among grain yield components showed the high significance according to the clipping method, and that there showed little variation for other yield components due to the sowing date and clipping method. There showed more grain yield in non-clipping rather than that of clipping plot, indicating the difference of 46kg/10a. This was resulted from short culm and severe winter damages caused by clipping before winter season. Of the grain yield components, number of spikes/㎡ was greatly influenced for grain yield by analysis of stepwise regression. Therefore, grain yield of rye was able to produce after forage utilization before winter season due to the appropriate crop and soil managements, by resulting from the little variation in grain yield between clipping or non-clipping plots and from the higher grain yield by the early sowing.

• Korean Journal of Organic Agriculture
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• v.28 no.2
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• pp.251-261
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• 2020

The developmental ecology and temperature-dependent growth model were calculated to develop the Scotinophara lurida control technology, which is mainly affected by environmentally friendly rice cultivation. The survival rate of S. lurida after overwintering in 2019 showed that 167 of 224 survived and the survival rate was 72.8%. Overwintering adult of S. lurida occur in rice fields in mid-June, spawn in early July, and first-generation adults develop in mid-August. In order to determine the temperature-dependent growth model, the growth periods by temperature and development stage were investigated in a incubator at 18, 21, 24, 27, 30℃ and 14L: 10D. The period from egg to adult at the temperature of 18, 21, 24, 27, 30℃ was 119.8, 73.1, 53.5, 39.4, and 82.0 days, respectively. The best development temperature was at 27℃. The regression curve was obtained by analyzing the relationship between temperature and growth rate using the Excell program, and the base temperature threshold and effective cumulative temperature for each development stage were calculated. From eggs to 5 nymphs of S. lurida the base temperature threshold was 17.9℃ and the effective cumulative temperature was 380.2 DD.

• Korean Journal of Plant Resources
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• v.27 no.2
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• pp.188-193
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• 2014

The sap outflow characteristics of Juglans sinensis and J. mandshurica were investigated to evaluate the optimum pruning period of walnut tree that there is a sap spill on dormant. The total period of sap outflow were 34 days for both J. sinensis and J. mandshurica. Total amount of sap outflow per tree in J. sinensis and J. mandshurica were 2,922 mL/tree and 3,135 mL/tree, respectively and the period of sap outflow and non sap outflow between two species were similar. ANOVA analysis showed that the amount of sap outflow was significant differences with day of sap outflow but there were no significant differences between species. From the correlation analysis between air-temperature and sap outflow, daily minimum temperature showed a positive correlation at the 1% level of significance (r=0.56 and r=0.46) for both J. sinensis and J. mandshurica. When branch of walnut tree that diameter is 5 cm cut on the period of sap outflow, the sap flowed down the longest period (48 days) but the sap outflow was not observed after budburst. Therefore, our study supported that the pruning have to avoid the period of sap outflow to reduce sap outflow of walnut tree.

• Research in Plant Disease
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• v.19 no.2
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• pp.108-113
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• 2013

Wilt damage on tomato plants caused by Ralstonia solanacearum has been increased as the areas of tomato cultivation increased during the warm seasons. Also, the tomato rootstocks used to prevent the disease occurrence are not effective in the highly prevailing regions. Therefore, bacterial wilt resistant eggplant rootstock EG203, collected from AVRDC, was tested for its effect to deter the Ralstonia solanacearum wilt disease in the greenhouses at Buyeo Tomato Experiment Station from 2003 to 2005, and at Gumi, Kyungpook province from 2009-2011. Planting of eggplant rootstock EG203 should be done three weeks before the planting of tomato scions so that they can have similar stem diameter (2.5-3.0 mm) and can be easily grafted. Both insertion and inarching grafting showed 93-96% success rates. In the greenhouse tests at Buyeo Tomato Experiment Station from 2003 to 2005, eggplant rootstock EG203-grafted tomatoes showed the disease occurrence of 4.3%. On the other hand, non-grafted or other commercial rootstock-grafted tomatoes showed disease occurrence of 58.0% and 25.0-36.7%, respectively. In the greenhouse tests at Gumi, Kyungpook province in 2009, the disease occurrence on the EG203-grafted and non-grafted tomatoes was 2-5% and 20-80%, respectively. In 2010, at Gumi, Kyungpook province, when the wilt disease occurred slightly, the tomatoes grafted with tomato rootstocks B-blocking and Chung-gang, and eggplant rootstock EG203 showed similar disease severities, but EG203-grafted tomatoes formed lately cluster, resulting in the reduction of yield compared to tomato-grafted tomatoes. In 2011, at Gumi, Kyungpook province, when the wilt disease occurred severely, the tomato rootstocks 'B-blocking' and Chung-gang and eggplant rootstock EG203-grafted tomatoes showed disease occurrences of 60-85% and 0-1%, respectively. Therefore, it was concluded that tomato rootstocks 'B-blocking' and 'Chung-gang' are more useful in the areas contaminated with low levels of pathogen and eggplant rootstock EG203 is more useful in the areas contaminated with high levels of pathogen.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.318-329
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• 2014

In order to gain insight into the physiological responses of plants to high temperature stress, the effects of temperature on Chinese cabbage (Brassica campestris subsp. napus var. pekinensis cv. Detong) were investigated through analyses of photosynthesis and chlorophyll fluorescence under 3 different temperatures in the temperature gradient tunnel. Growth (leaf length and number of leaves) during the rosette stage was greater at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures than at ambient temperature. Photosynthetic $CO_2$ fixation rates of Chinese cabbage grown under the different temperatures did not differ significantly. However, dark respiration rate was significantly higher in the cabbage that developed under ambient temperature relative to elevated temperature. Furthermore, elevated growth temperature increased transpiration rate and stomatal conductance resulting in an overall decrease of water use efficiency. The chlorophyll a fluorescence transient was also considerably affected by high temperature stress; the fluorescence yield $F_J$, $F_I$, and $F_P$ decreased considerably at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures, with induction of $F_K$ and decrease of $F_V/F_O$. The values of RC/CS, ABS/CS, TRo/CS, and ETo/CS decreased considerably, while DIo/CS increased with increased growth temperature. The symptoms of soft-rot disease were observed in the inner part of the cabbage heads after 7, 9, and/or 10 weeks of cultivation at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures, but not in the cabbage heads growing at ambient temperature. These results show that Chinese cabbage could be negatively affected by high temperature under a future climate change scenario. Therefore, to maintain the high productivity and quality of Chinese cabbage, it may be necessary to develop new high temperature tolerant cultivars or to markedly improve cropping systems. In addition, it would be possible to use the non-invasive fluorescence parameters $F_O$, $F_V/F_M$, and $F_V/F_O$, as well as $F_K$, $M_O$, $S_M$, RC/CS, ETo/CS, $PI_{abs}$, and $SFI_{abs}$ (which were selected in this study), to quantitatively determine the physiological status of plants in response to high temperature stresses.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.2
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• pp.75-82
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• 2008

In order to establish environmentally friendly phosphorus(P) and potassium(K) fertilizer application rates for rice cultivation in Korea, a field experiment was conducted in two different characterized paddy soils, higher and lower P and K content in soil from 2005 to 2006 in Suwon, Korea. Chuchong which is typical rice variety in Korea, was selected for experiment. Rice yields in base P-K fertilizer level ($30-30kg\;ha^{-1}$) and no P-K fertilizer level were 97~98% and 93~97% of standard P-K fertilizer level ($45-57kg\;ha^{-1}$), respectively. At the lower content of P and K in immatured paddy soil, the yield of no P plot was decreased by 7% compared to that of standard P-K plot. Significant difference in rice yield and yield characteristics was found neither in standard P-K fertilization plot nor in base P-K fertilization plot. There was no significant difference in P and K uptake at the harvest stage between standard P-K fertilizer plot and base P-K fertilizer plot. Phosphorus and K uptake was slightly decreased in no fertilizer plots compared to standard fertilizer plot. Phosphorus and K use efficiency of rice plant in base fertilizer plot was higher than that in standard fertilizer plot. Available phosphorus and exchangeable potassium content in soil at the harvest stage were increased in both standard and base fertilizer plot. But no significant difference of P and K content in ? was found between standard fertilizer plot and base fertilizer plot. Rice quality characteristics such as proportion of brewers rice, damaged kernel, broken rice, and content of amylose and protein were lowered in the base fertilizer plot than the standard fertilized plot, while the proportion of perfect kernel increased in the base fertilizer plot From the results, we generally recommend the base P-K fertilization ($30-30kg\;ha^{-1}$) instead of standard P-K fertilization ($45-57kg\;ha^{-1}$) for rice cultivation in Korea.

• Journal of International Area Studies (JIAS)
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• v.22 no.2
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• pp.217-244
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• 2018

As Chinese insurance market grows rapidly due to market reforms, China got recognition as second-largest insurance market in the world in 2016. However Korean insurance companies have had difficulties to grow in Chinese insurance market despite Chinese participation in the World Trade Organization (WTO) and the growth of chinese insurance market. The reason for the decline in Korean insurance companies is economic retaliation due to the deployment of THAAD in Korea. However, this is not a fundamental reason. The underlying cause of the effects of economic retaliation is the result of insufficient negotiations in Korea-China FTA services sector. In Service sector of Korea-China FTA, the level of concession between Korea and China differs greatly, when comparing China and South Korea's FTA. In addition, it has only been a few years since China collected the position of the WTO Doha Agenda, which currently deals with concessions on intellectual property rights and services. More important is that the Korea-China FTA service sector, as it stopped short of being protected by the most-favored-nation state treatment level when Korean insurance companies entered China. Further negotiations to supplement the weak points in the Korea-China FTA service sector were promised in December 2017, but international tensions over THAAD deployment made it impossible to hold such negotiations. However, due to changes in international affairs in 2018, the first additional negotiation was decided and held. This paper implicates strategies of further negotiation between Korea and China for service and investment chapter. Consequently, the aim of this paper suggests directions how to re-enter Chinese insurance market to Korean insurance companies.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.41-51
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• 2015

The purpose of the Follies that were constructed for the Gwangju-Biennale were for urban regeneration, to activate the empty old-town areas, and to strengthen the tradition and sense of place of the city. However, the ten Follies constructed around the wall of the old castle reveal many problems including that of leaving Follies alone instead of actively using them, damage to shop-keepers nearby, and pedestrian inconvenience, which is different from the original purposes. This study is meant to help understand the source of the negative phenomena, and to offer plans that will be conductive to the role of urban regeneration through activating the Follies and the spaces around them. As results of the investigation, there was no context giving uniformity among the various Follies. Also, the study showed that the insufficience of designers' understanding of the circumference near the Follies and lack of a consensus between the citizens and designers in the process of making the Follies. The crucial solution for solving these problems, and bringing to life the original purpose of creating the Follies was derived as applying "human activity" to the Follies. This study suggested 'street performance' as an effective device for application to human activity. While a Folly has no fixed function, the development of space program categories based on the applied characteristics of each Folly, and the simulation thereof showed effective potential for attracting people and activating those stagnated spaces. Recently, Gwangju city depicted the second Follies in applications such as reading roon, toilet, and movable food cart, which have clear purpose and different characteristics from the first ones. However, the first Follies will not be moved or demolished. As they are located around the National Asia Culture Center, some of them are supposed to be used to view the center. Consequently, a counterplan for the continuous and efficient use of those Follies is needed. Gwangju has a plan for the installation of 100 Follies throughout the city and it is expected that this study will be a meaningful guide line for improved Follies in the future.