• Korean Journal of Medicinal Crop Science
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• v.14 no.1
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• pp.8-13
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• 2006

This study was carried out to investigate drying methods for keeping freshness and active components of aerial part of Saururus chinensis. Chopped samples were prepared using hot air drying, hot air drying + roasting, presteamed + hot air drying, freeze drying, and sun drying. Drying time was shorter $88{\sim}93%$ in hot air drying and freeze drying than in sun drying. Percentage of dry matter was higher in the order of freeze drying > sun drying > hot air drying, and moisture content in the order of sun drying > hot air drying > freeze drying. The contents of total phenolics and quercetin related substances were greater in the order of freeze drying > hot air drying > sun drying, while were decreased due to treatments before or after hot air drying. Electron donating ability (EDA) was highest in freeze drying, and showed a little difference between hot air drying and sun drying, but was increased because of treatments before or after hot air drying. In color values, the a value was lower in the order of freeze drying < hot air drying < sun drying. The contents of active components of plant parts of hot air dried were higher in the order of flower >leaf > chopped sample > stem. EDA showed similar tendency with those. The a value was lower in the order of leaf < chopped sample < flower < stem. As a result, freeze drying of chopped samples or hot air drying of leaf and flower were effective to maintain qualities of aerial part of Saururus chinensis.

• Korean Journal of Medicinal Crop Science
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• v.18 no.3
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• pp.168-172
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• 2010

This experiment was carried out to investigate the effect of several organic compost on the growth and root yield of Scutellaria baicalensis G. with organic cultivation from 2008 to 2009. Four organic compost were used ; Rice bran compost (RC : 1.1-3.6-1.4), Wheat bran compost (WC: 1.1-3.4-1.4), Hangawi compost (HC : 3.7-4.0-1.0), Cheonnyeonjigi compost (CC : 12.4-3.4-5.4) and Fermented chicken droppings compost (FC : 2.9-6.1-3.2). Organic matter, available phosphate and $K_2O$ of soil increased in all plots with the addition of organic compost, specifically in HC, CC and FC application. Treatment of HC, CC and FC application increased emergence rate and improved the growth characters of shoot, root parts of plants compared to those of RC application. Subterranean part yields by different organic compost was high 149~156 kg per 10a as by growth increment of dried root yield. length of main root and diameter of main root. respectively, 17.4~18.4 cm, 12.65~12.94 mm from HC, CC and FC application. There were significantly positive correlation between the growth characters of shoot, root parts of plants, dry root yield in Scutellaria baicalensis G. grown under organic compost application.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.117-121
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• 2001

This study was carried out to investigate the effects of rice cultivation of no-tillage seeding on the physicochemical properties and rice yield in the paddy soil of Milk vetch (Astragalus sinicus L.) established. The number of Milk vetch establishment was 256 per $m^2$ in the before experiment but 440 per $m^2$ in the after experiment. The seed numbers of Milk vetch were sufficient that Milk vetch seed were not sown again in the next year. Soil physicochemical properties of the plot of Milk vetch cultivation were similar to the conventional plot. The amount of weed occurrence was 87g dry weight per $m^2$ in the conventional but not occurrence in the sowing of Milk vetch establishment. Rice yield was 4.9ton per ha in the conventional and 4.5 ton per ha in the soybean seeder sowing of Milk vetch establishment.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.4
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• pp.218-221
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• 2005

The present study was investigated in the Chittagong hill forest of Bangladesh to assess the feasibility of ginger cultivation under multipurpose forest and fruit tree species. There were three treatments such as i) ginger grown under open field condition, ie. full sunlight (T1), ii) ginger grown under Gamar tree (spacing of $90{\times}90cm$ (T2) and iii) ginger grown under guava tree (spacing $180{\times}180cm$) tree (T3). The experiment was laid out in randomized block design (RBD) and each treatment was replicated three times. From data it was observed that some morphological parameters of ginger such as plant height, number of leaves per plant, leaf length and leaf breadth were higher in the treatments T2 and T3 as compared to the treatment T1. A positive and linear relationship was observed between the weight of rhizome and yield of ginger which caused the highest yield of ginger ($23.63Mg\;ha^{-1}$) under guava tree species at partial shaded condition in the T3 treatment ($180{\times}180cm$), whereas the lowest yield ($15.64Mg\;ha^{-1}$) was recorded in the T2 treatment when ginger was cultivated under Gamar tree species at closer spacing ($90{\times}90cm$). Therefore, it was revealed that partial shaded condition favoured the optimum growth and yield of ginger, whereas the dense shade from intensively planted tree species badly affected the dry matter production and yield of ginger.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.105-111
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• 2013

The experiments were carried out to investigate the biocontrol potential of Lysobacter capsici YS1215 on root-knot nematode and to characterize its lytic enzyme activities. L. capsici YS1215 showed chitinase and gelatinase activities on the medium containing 0.5% chitin or 0.5% gelatin as substrates. Cell growth of L. capsici YS1215 was highest at 6 days, and the highest activities of chitinase (4.0 unit $ml^{-1}$) and gelatinase (7.43 unit $ml^{-1}$) were observed on 3 and 5 days after incubation, respectively. To investigate the effect of L. capsici YS1215 on tomato growth and nematode infection, the plants in pot trial were treated with bacterial culture (BC), half of bacterial culture (HBC), only bacterial medium (BM), tap water (TW) and commercial nematicide (CN). HBC treatd plants showed the higher shoot fresh weight and dry weight on $5^{th}$week after incubation while BM, HBC and BC had consistently higher values than TW at $9^{th}$ week. HBC appeared to be the highest shoot fresh length at $9^{th}$ week. Both CN and BC showed lower number of egg mass, root gall, and population of juveniles in soil compared to BC, HBC, BM and TW. These results suggest that L. capsici YS1215 with its strong ability of lytic enzyme production can be one of the most significant candidates for biocontrol agents against root-knot nematodes.

• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.217-224
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• 2011

of materials and simplification of process. Micro-blasting is one of the promising method for recycling of waste wafer due to their simple and low cost process. Therefore, in this paper, we make recycling wafer through the micro-blaster. A surface etched by micro-blaster forms particles, cracks and pyramid structure. A pyramid structure formed by micro-blaster has a advantage of reflectivity decrease. However, lifetime of minority carrier is decreased by particles and cracks. In order to solve this problems, we carried out the DRE(Damage Romove Etching). There are two ways to DRE process ; wet etching, dry etching. After the DRE process, we measured reflectivity and lifetime of minority carrier. Through these results, we confirmed that a wafer recycled can be used in solar cell.

• Journal of Korea Water Resources Association
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• v.32 no.6
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• pp.617-625
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• 1999

Global warming has begun since the industrial revolution and it is getting worse recently. Even though the increase of greenhouse gases such as $CO_2$ is thought to be the main cause for global warming, its impact on global climate has not been revealed clearly in rather quantitative manners. However, researches using General Circulation Models(GCMs) has shown the accumulation of greenhouse gases increases the global mean temperature, which in turn impacts on the global water circulation pattern. This changes in global water circulation pattern result in abnormal and more frequent meteorological events such as severe floods and droughts, generally more severe than the normal ones, which are now common around the world and is referred as a indirect proof of global warming. Korean peninsula also cannot be an exception and have had several extremes recently. The main objective of this research is to analyze the impact of global warming on the change of flood and drought frequency. Based on the assumption that now is a point in a continuously changing climate due to global warming, we analyzed the observed daily rainfall data to find out how the increase of annual rainfall amount affects the distribution of daily rainfall. Obviously, the more the annual rainfall depth, the more frequency of much daily rainfall, and vice versa. However, the analysis of the 17 points data of Keum river basin in Korea shows that especially the number of days of under 10mm or over 50mm daily rainfall depth is highly correlated with the amount of annual rainfall depth, not the number of dry days with their correlation coefficients quite high around 0.8 to 0.9.

• Journal of Wetlands Research
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• v.20 no.3
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• pp.281-293
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• 2018

Wetlands of Dongbaekdongsan were classified into two types of pond and vernal pool. 11 plant communities are established there such as Nymphoides indica community, Sparganium stoloniferum Community, Persicaria hastato-auriculata community, Scirpus triangulatus community, Triadenum japonica community, Juncus papillosus community, Deinostema violacea community, Centipeda minima community, Apocynum sibiricum community, Isachne globosa community, and Ulmus parvifolia community. Nymphoides indica community is established in a pond located on the entrance of the Dongbaekdongsan and Persicaria hastatoauriculata community appears on edge of the pond. Sparganium stoloniferum community is formed in nearby pond with relatively shallow water and Persicaria hastatoauriculata community is established on margin of the pond. Vernal pools had been used for drinking water source and for livestock in some cases in the past. Scirpus triangulatus community is established in the most wet site as the center of the pools and Juncus papillosus community - Deinostema violacea community - Triadenum japonica community, and Apocynum sibiricum community appear in a concentric circle pattern as far away there. Ulmus parvifolia community is established in a dry vernal pool. This is the first study on vernal pool carried out in Korea. Therefore, most vegetation types are new ones different from existing studies on wetland.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.170-175
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• 2013

Korea is carrying out weed quarantine by plant quarantine regulations including heat-treatment method to prevent the influx of exotic weeds. In order to confirm suitability for current heat-treatment criteria and find field-applicable methods which can completely devitalize quarantine weed seeds, the conditions for heat-treatment with/without 40% relative humidity were studied with 9 species among quarantine weed seeds and one weed species similar to quarantine weed. Dry heat-treatments had been tested under various temperatures and time conditions. All seeds were dead at the conditions of $95^{\circ}C$ for 48 hours, $100^{\circ}C$ for 36 hours, $110^{\circ}C$ for 24 hours, $121^{\circ}C$ for 4 hours and $130^{\circ}C$ for 30 minutes. Heat-treatments at 40% relative humidity resulted in complete seed death at the conditions of $85^{\circ}C$ for 36 hours and $90^{\circ}C$ for 16 hours. The above results show that current heat-treatment criteria are not suitable for several quarantine weeds and these conditions could be applied as a quarantine method to prevent the influx of quarantine weeds along with agricultural imports. More specific conditions for heat tolerant species such as Picris echioides and heat susceptible species such as Cuscuta spp. are necessary and will improve plant quarantine process in devitalizing quarantine weed seeds with different heat tolerances.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.2
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• pp.110-115
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• 2011

Objectives: The aim of this study is to survey for finding asbestos containing equipment at the laboratories using picture based questionnaire and polarized light microscopic analysis. Methods: This study was conducted from 2009 to 2010 at a university in Seoul. In 2009, picture based questionnaire was distributed to 100 laboratories during the regular laboratory air quality monitoring. In 2010, we emailed all professors of the same university who have laboratories to participate voluntarily this survey. For the laboratories consented to participate survey, picture based questionnaire was distributed and collected. Suspected asbestos containing material and apparatus were collected at the laboratories which replied they have suspected material and equipment. Collected samples were analyzed with polarized light microscope at the laboratory accredited by ministry of employment and labor in Korea. Results: Total of 18 out of 100 laboratories reported that they had suspected asbestos containing equipment in 2009. Twenty-three samples were collected and three samples (13%), one heating mantle and two pairs of insulation gloves, contained asbestos. Thirty four laboratories reported they had suspected asbestos containing material or equipment in 2010. Sixty samples were collected and four of them (6%), two pairs of insulation gloves, one packing rope in dry oven and, one pair of tongs, contained asbestos. All founded asbestos was chrysotile and the content of chrysotile was more than 90% for all equipment except heating mantle which has less than 1%. Conclusions: We confirmed that asbestos was still used at the laboratories though strict regulations on asbestos use in Korea. The method of picture based questionnaire invented in this study could be applied for asbestos survey to other research institute or university where there are many laboratories because of its simplicity and accessibility without huge man power, cost and time.