• Korean journal of applied entomology
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• v.24 no.3 s.64
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• pp.117-121
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• 1985

Through the laboratory and vinyl house experiments, the effects of inoculum density, plant age and temperature on the incidence of Phytophthora crown rot of pepper (Capsicum annum L.) were investigated. The propagule survival was greater in the natural soil than in autoclaved soil within first 2 weeks when the sporangial suspension of the pathogenic fungus was incorporated into soil, thereafter the survivability reduced rapidly. The propagule was not detectable in 35 days by means of Papavizas selective medium neither in natural nor in autoclaved soil. At least 5 sporangia per gram soil were required to induce crown rot for 30 days old pepper seedlings. Further increase in inoculum concentration above this threshold level resulted in higher disease incidence and shorter incubation period. When the same amount of inoculum was infested, higher disease incidence was observed for younger plants until 3 weeks after inoculation. On the other hand after 4 weeks this tendency was not extended any more. Younger plants were recognized as having shorter incubation period upon infection, however, the days from first symptom appearance to complete death were not significantly different among differently aged seedlings. Exposure of inoculated pepper seedlings to $25^{\circ}C$ resulted in highest infection rates and followed by those to $30^{\circ}C\;and\;20^{\circ}C$ but no disease was found at $15^{\circ}C\;and\;35^{\circ}C$ for 10 days. When the plants previously incubated at different temperature for 10 days were moved to $25^{\circ}C$ room temperature, prior exposure to $20^{\circ}C\;and\;30^{\circ}C$ brought continuous disease development. Even those plants preincubated at $15^{\circ}C$ were diseased up to 50%. But the prior exposure to $35^{\circ}C$ induced no symptom developed, indicating no seedlings infected at all.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.625-628
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• 2015

POLARBEAR is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic inflation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1.274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.

• Journal of the Korean Magnetics Society
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• v.27 no.2
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• pp.41-48
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• 2017

Recent study shows that ordered alloy of $L1_2$ $XPt_3$ (M = V, Cr, Mn, Co, and Fe) exhibits various magnetic phases such as ferromagnetic-to-antiferromagnetic transition at the $MnPt_3$ surface. Moreover, it has been argued that $CrPt_3$, in particular, possess large magnetocrystalline anisotropy and Kerr rotation with possible violation of Hund's rule. As such, we extend our work to thickness dependence of the magnetic structure of $CrPt_3$ thin film using density functional theory. Magnetic ground state of the bulk $CrPt_3$ turns out to be ferromagnetic (FM), where other magnetic phases such as A-type (A-AF), C-type (C-AF), and G-type antiferromagnetic (G-AF) state have higher total energies than FM by 0.517, 0.591, and 0.183 eV, respectively, and magnetic moments of Cr in bulk are respectively 2.807 (FM), 2.805 (A-AF), 2.794 (C-AF) and $2.869_{{\mu}_B}$ (G-AF). We extend our study to $CrPt_3$(001) thin films with CrPt-and Pt-termination. The thickness and surface-termination dependences of magnetism are investigated for 3-9 monolayers (ML), where different magnetic phases from bulk emerge: C-AF for CrPt-terminated 3 ML and G-AF for Pt-terminated 5 ML have energy difference relative to FM by 8 and 54 meV, respectively. Furthermore, thickness- and surface-termination-dependent magnetocrystalline anisotropies of the $CrPt_3$(001) films are discussed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.3
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• pp.203-208
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• 2012

Pyeongangok, a new single cross variety, is an yellow dent maize hybrid (Zea mays L.) developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2011. This hybrid, which has a high yield of grain and dry matter, was produced by crossing two inbred lines, KS160 and KS155. KS160 is the seed parent and KS155 is the pollen parent of Pyeongangok. Silking date of Pyeongangok is 2 days earlier than that of check hybrid, Jangdaok, and equal to that of another check hybrid, Kwangpyeongok. Plant height of Pyeongangok is longer than that of Jangdaok and similar to that of Kwangpyeongok. Ear numbers per 100 plants of Pyeongangok is more than that of Jangdaok. Ear length of Pyeongangok is shorter than that of Jangdaok. 100 seeds weight of Pyeongangok is lighter than that of Jangdaok. Ear rate of Pyeongangok is lower than that of Kwangpyeongok. Stay-green of Pyeonganok is not greatly different with that of Kwangpyeongok. It has moderately resistance to southern corn leaf blight (Bipolaris maydis), black streaked dwarf virus (BSDV) and corn borer. It has strong resistance to northern corn leaf blight (Exserohilum turcicum). It has resistance to lodging. Pyeongangok was evaluated for the yields of grain and dry matter at four locations from 2009 to 2011. The yield of Pyeongangok in grain was 7.66 ton/ha. The yield of Pyeongangok in dry matter was 19.80 ton/ha. The yield of Pyeongangok in total digestible nutrient (TDN) was 13.32 ton/ha. Seed production of Pyeongangok has gone well due to a good match during crossing between the seed parent, KS160, and the pollen parent, KS155, in Yeongwol.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.327-336
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• 2016

The Bagan, the central part of Myanmar, is dry zone where the mean annual precipitation is less than 600 mm for the last ten years. Forest in this region has been degraded due to biotic and abiotic disturbances. While there have been various efforts to rehabilitate the degraded area, the information on growth and physiological characteristics of planting species and the impacts of planting trees in the region still lacks. Therefore, this study was conducted to determine the growth and physiological water use efficiency characteristics of five species (Azadirachta indica A. Juss., Acacia catechu Willd., Eucalyptus camaldulensis Dehn., Acacia leucophloea (Roxb.) Willd. and Albizia lebbek (L.) Willd.) which are utilized as rehabilitation species in the dry zone and to identify the impacts of tree planting on microclimate change in dry zone. The growth and the foliar carbon isotope composition of seedlings and the above mentioned five species planted in 2005 were measured. And from February 2015 to January 2016, microclimatic factors air temperature and relative humidity at 60 cm and 2 m above soil, soil temperature, soil water contents and precipitation were measured at every 30-minute interval from the two weather stations installed in the plantation located in Ngalinpoke Mt. Range. One was established in the center of A. indica plantation, and the other was in the barren land fully exposed to the sunlight. Among the five species, A. indica and A. lebbek which showed higher water use efficiency could be recommended as rehabilitation species in dry zone. Planting trees in the dry area was shown to affect the change of microclimate with shading effects, declining temperature of the land surface and aridity of the air, and to contribute to conserving more water in soil by preventing direct evaporation and containing more water with fine roots of trees.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1439-1445
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• 2013

The aim of this study was to investigate the quality characteristics of rice cookies specifically prepared with rice flour following enzyme treatment. In this study, three types of specific enzyme treatments, that is, ${\alpha}$-amylase, ${\beta}$-amylase, and cellulose+${\beta}$-glucanase were applied on the effect of rice flour with respect to desired quality characteristics of the rice cookies. Based on our study results, we have found that the density of dough in the rice cookies was not significantly different between that of the non-enzyme treated (control) and the enzyme treated group. However, we found that the spread factor of rice cookies, prepared with rice flour treated with ${\beta}$-amylase, was higher than that of the control. It was also found that the moisture content of rice cookies (with added enzyme-treated rice flour) was 3.20 to 3.90%; however, this range is much lower than that observed in the control. Further, we observed that Hunter color's L-values were significantly higher for the control than those of the enzyme-treated cookies. We also found that hardness of enzyme-treated cookies was comparatively better than that of the control. In addition, the sensory acceptability scores of the enzyme-treated cookies were found to be significantly higher than the control in decisive parameters such as aroma, appearance, flavor, taste, texture, and overall acceptability. Based on our findings, we suggest that ${\alpha}$-amylase treated rice flour is an effective ingredient for improving the overall quality of rice cookies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.706-713
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• 2012

This study was carried out to investigate the contents of monacolin K and citrinin, along with the sensory quality and antioxidant activity of mulberry leaf tea fermented by $Monascus$ $pilsous$ (FMM). Total monacolin K content of FMM was 0.058%, but citrinin was not detected. Redness of brewed FMM was remarkably higher than that of unfermented mulberry leaf tea (UFM). In sensory evaluation of brewed FMM, while astringent taste and savory taste were lower, flavor, color, and overall acceptability were significantly higher than those of UFM. Total polyphenol contents of UFM and FMM were 83.1 and 23.61 mg/g (dry basis), total flavonoid contents of UFM and FMM were 17.96 and 3.99 mg/g (dry basis), respectively. Xanthine oxidase (XO) inhibitory activity and superoxide dismutase (SOD)-like activity of FMM were lower than those of UFM. Electron-donating ability and ferric-reducing antioxidant power of FMM were slightly lower than those of UFM. However, the antioxidant activities of FMM per polyphenol content were markedly higher than those of UFM. These results suggest that FMM may scavenge excessive reactive oxygen spices (ROS) via inhibition of XO and SOD-like activity. Furthermore, FMM demonstrated relatively higher acceptability and antioxidant ability along with functionality of $Hongguk$ (red yeast rice), and therefore could be utilized to prevent various ROS-induced diseases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.183-192
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• 1982

The variability of rice productivity during last 2 decades (1961-1980) of ten years before and after the introduction of"Tongil" was reviewed from the epochal, regional and varietal points of view. During that period the cultivated area of paddy rice have remained almost unchanged, while the total rice production have got elevated from 3, 463 million metric tons in 1961 to 6.006 million metric tons in 1977, recording 73.4% increase. This remarkable increase in rice production is considered to be attributable much to the development and release of new high yielding variety, "Tongil", coupled with the amelioration of cultural techniques. However, in 1978 Tongil type varieties experienced the epidemic outbreak of blast disease due to the shifted race population of blast fungus and in 1980 recorded poor rice production as low as in 1960's due to the unfavorable weather stress throughout the rice growing season, giving rise to many problems awaiting solutions for securing the stabilized high production of rice. The rice yield has continued the gradual increase during last two decades but its difference between farmer and research organization have got wider from 79kg/10a during 1960 to 1971 to 101kg/l0a during 1972 to 1980, and also the inter-regional differences have been increased from 50-60kg/10a to 80kg/10a during those periods. Therefore, this proves that we have raised the upper boundary of rice yield by increasing the yield potential of rice variety but have not changed those absolute deviations. Estimates indicate that the increased rice production during that period was indebted 40 percent to the varietal improvement and 13 percent to the ameliorated agro-technologies, and the rest, 47 percent, could be ascribed to the other factors besides varieties and cultural technologies such as the improved agricultural environments, etc. Of course, even though it cannot be expected to unify the cultural environments and the cultural technologies, provided that much efforts are to be endeavored to minimize the yield difference of 20 percent between farmer and research organizations and the inter-regional yield difference of 20 percent, much increased rice production can be expected to be achieved with the current level of cultural technology and the yielding potential of the present rice varieties. In order to expedite the above effects on rice production the followings are to be put into practices consitently and steadfastly. 1. Reinforcement of breeding for varieties with high yielding potential and less susceptible to climatic-stress and pests, and of basic physicoecological studies of rice plant for improving the cultural technologies. 2. Continuous endeavor to secure the stabilized cultural environments by improving the soil fertility and increasing the drainage and irrigation facilities. 3. Political back-up to encourage the farmers' incentives for production 4. Precise surveys for agricultural statistics to facilitate the long-term planninge long-term planning.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.111-118
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• 2010

Stress due to excess water is one of the most limiting factor for soybeans to high yield under wet climates. This study aimed to identify the photosynthetic responses of soybeans to waterlogged growing condition with 5 soybean varieties by waterlogging for 10 days at V5 and R2 stage, respectively. Chlorophyll fluorescence decreased more rapidly at R2 stage waterlogging than at V5 stage waterlogging in all soybean tested varieties. The degree of recovery was much more in Pungsannamulkong and Muhankong( 95～97% of control) than in Jangyeobkong and Myungjunamulkong at 5 days after waterlogging. Photosynthetic rate, transpiration and stomatal conductance were also increased more rapidly in Pungsannamulkong and Muhankong than in Jangyeobkong and Myungjunamulkong after waterlogging irrespective of waterlogging stages. As the result of multiple regression analysis in order to identify the effects of stomatal conductance and transpiration to the photosynthetic rate, the R2 value of stomatal conductance in control and waterlogging treatment was 0.7293 and 0.7582, respectively. If the transpiration, another dependent variable, was added to the regression formula, there was not so big difference in the variation of photosynthetic rate. This result means that if just one factor of them(the stomatal conductance and transpiration) be measured in the case of waterlogged condition, the changes of photosynthetic rate can be estimated.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.316-322
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• 2011

BACKGROUND: Pesticides concentration was monitored in 50 agricultural lakes, and ecological risk for aquatic organism was assessed using risk quotient (RQ) and probabilistic methods. METHODS AND RESULTS: Pesticides concentrations detected in 50 agricultural lakes during peak season (June and September) were in the range of $0.17{\sim}0.99{\mu}g/L$. The RQ for algae and the other species was estimated to be 0.25 and below 0.01, indicating medium risk and no risk. Oxadiazon predominantly contributed to RQ value of 99% for algae, fishes, and amphibians. In terms of hazardous concentration at 5% of species ($HC_5$), ecological risk quotients (ERQ) for oxadiazon ranged from 0.18~0.33, showing a medium risk level. Overall, the concentrations of pesticides were much lower than $HC_5$), value. Probability of combined ecological risk for pesticides ranged from 1.82% to 2.41%. CONCLUSION(s): Combined ecological risk probability did not exceed the acceptable level of 5%, indicating no ecological risk for selected aquatic species. This study suggests that regular ecological risk assessment (ERA) will be required to protect and manage an agricultural lake. Not only ERA at screening level by comparing exposure with toxic effects for aquatic species also advanced ERA technique considering species in indigenous to Korea, chronic toxicity, pulse dose, fate, and environmental factors should be required.