• Korean Journal of Weed Science
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• v.3 no.1
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• pp.105-110
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• 1983

In order to select the effective herbicides on polyethylene film mulching culture of galic (Allium sativum L) for weed control in early and low temperature condition, several experiments were conducted at the Chungbuk Provincial Office of Rural Development from 1978 to 1982. The dominated weed in the open field was Chenopodium album (98.1%), and there were many Rvrippa globosas (39.7%), and Dtgitaria sanguinalis (34.3%) in the polyethylene film mulching culture. Effective herbicides in polyethylene film culture were alachlor EC, pendimethalin EC, oxyfluorfen EC, and acifluorfen EC. After the 15th May, metabenzthiazuron WP and prometryne WP for the gramineous weeds were effective. There was a little chemical injury on acifluorfen EC application, but not another influence on the yield. With the effective herbicides application in the polyethylene film mulching culture, yield (22-23%) and profits (26.84) to the nonmuiching culture were increased. Increase of yield (20%) and profits (56%) in black opaque polyethylene film mulching culture compared with the conventional culture was possible.

• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.85-91
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• 2004

This study was conducted to investigate the effects of dietary direct-fed microbials(DFM) on the growth performance and nutrient digestibility in broiler chickens. A total of two hundred eighty eight broiler chickens were randomly allocated into six treaments with four replications and fed for five weeks. Dietary treatments included 1) CON (basal diet), 2) DFM-1(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri), 3) DFM-2(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus plantarum), 4) DFM-3(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri ＆ Lactobacillus plantarum), 5) DFM-4(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri ＆ Lactobacillus plantarum ＆ Yeast), 6) DFM-5(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri ＆ Lactobacillus plantarum ＆ Bacillus subtilis). During the period of 1∼3weeks, average daily gain (ADG) and Feed/Gain were not significant different among treatments. In the later(3∼5weeks) and overall period(l∼ 5weeks), ADG and Feed/Gain tended to be improved in DFM treatments compared to the control. However, there were no significant differences among DFM complexes and between control and DFM treatments. The broilers fed DFM-3 diet was showd poor growth performance compared to the broilers fed DFM-l diet and similar to the broilers fed DFM-2 diet but there was no significant differences. The treatments of DFM-4 diet added Yeast and DFM-5 added Bacillus subtilis were improved in ADG and Feed/gain but no significant differences were found and also there was no specific DFM treatments in experiment period. In digestibility, the broiler chicks fed DFM treatments tended to improve N digestibility compared to control treatment. However, they were not significantly different among the treatments. In conclusion, DFM tended to improve growth performance in later stage of broiler.

• Korean Journal of Organic Agriculture
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• v.18 no.4
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• pp.573-586
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• 2010

This study was carried out to evaluate characteristics of Chrysanthemum sp. and to bioassay Tetranychus urticae, Nilaparvata lugens, and Aphis gossypii by different extracts part and method. Flower type of Chrysanthemum sp. line was anemone except 0706 line which was pompon. The flowering date was from April to June but 0721 line kept up November. They could overwinter except 0706 line. The Ethanol extracts of 0718 line of flower was high mortality as 63.8% on Tetranychus urticae. Ethanol mixed emulsifier extracts were the highest mortality as 69.4% at 5 days after. Mortality in water extract was lower than in ethanol and ethanol mixed emulsifier extracts. Ethanol mixed emulsifier extracts were higher mortality as 69.4% at 5 days after in 0718 line on Nilaparvata lugens. Mortality in water extract was lower than in ethanol and ethanol mixed emulsifier extracts. On Aphis gossypii, Chrysanthemum flower extracts could decrease the density of aphids in early days but the density of that was increase as time goes by because aphids produce offspring.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.86-91
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• 2008

Dicamba(3,6-dichloro-2-methoxybenzoic acid) is used to control for pre and post-emergence of annual and perennial broad-leaf weeds. It is very soluble in water and highly mobile, acidic herbicide. So it is easily moved and detected in groundwater. Zerovalent iron(ZVI) has been used for the reductive degradation of certain compounds through amination of nitro-substituted compounds and dechlorination of chloro-substituted compounds. In this study, we investigated the potential of ZVI for the oxidative degradation of dicamba in water. The degradation rate of dicamba by ZVI was more rapidly increased in pH 3.0 than pH 5.0 solution. The degradation percentage of dicamba was increased with increasing amount of ZVI from 0.05% to 1.0%(w/v) and reached above 90% within 3 hours of reaction. As a result of identification by GC-MS after derivatization with diazomethane, we obtained three degradation products of dicamba by ZVI. They were identified 4-hydroxy dicamba or 5-hydroxy dicamba, 4,5-dihydroxy dicamba and 3,6-dichloro-2-methoxyphenol. 4-Hydroxy dicamba or 5-hydroxy dicamba and 4,5-dihydroxy dicamba are hydroxylation products of dicamba. 3,6-dichloro-2-methoxyphenol is hydroxyl group substituted compound instead of carboxyl group in dicamba. We also confirmed the same degradation products of dicamba in the Fenton reaction which is one of oxidation processes using ferric sulfate and hydrogen peroxide. But we could not find out the dechlorinated degradation products of dicamba by ZVI.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.6 no.2
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• pp.129-139
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• 2003

Purpose: The aim of the study was to evaluate the long-term outcome of glycogen storage disease (GSD) type 1 with particular reference to hepatic adenoma and hepatocellular carcinoma, and to analyze risk factors affecting the development of hepatic adenoma in GSD type 1. Methods: Forty-three GSD type 1 patients (31 males and 12 females, mean age $13.9{\pm}6.4$ years) were analyzed retrospectively. Hepatic adenoma was detected on abdominal USG and diagnosed on histologic examination. Clinical profiles were compared between patients with hepatic adenoma (n=16) and age-matched controls without hepatic adenoma (n=16). Results: 1) Of 43 GSD type 1 patients, 16 (37.2%) had hepatic adeoma. Hepatic adenoma was detected at the age of mean $14.2{\pm}4.1$ years (range: 7.9~25.7 years). Fourteen (87.5%) adenomas were multiple at detection. 2) Comparison of the clinical profiles between adenoma group and non-adenoma group revealed that age at first introduction of uncooked cornstarch treatment was significantly late in adenoma group compared with non-adenoma group ($9.1{\pm}5.2$ years vs. $3.0{\pm}1.8$ years, p=0.003). Portocaval shunt surgery was performed in 11 (68.8%) patients in adenoma group and 3 (18.8%) in non-adenoma group (p=0.004). Hepatic adenoma developed mean $5.8{\pm}4.2$ years after shunt operation. 3) One patient was diagnosed as hepatocellular carcinoma at the age of 25.7 years. Conclusion: Hepatic adenoma is an important late complication of GSD type 1 with the risk of malignant transformation. Early introduction of cornstarch therapy with strict metabolic control is needed to prevent the development of hepatic adenoma in GSD type 1.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.161-161
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• 2003

During the last century, most scientific questions related to climate change were focused on the evidence of anthropogenic global warming (IPCC, 2001). There are robust evidences of warming and also human-induced climate change. We now understand the global, mean change a little bit better; however, the uncertainties for regional climate change still remains large. The purpose of this study is to understand the past climate change over Korea based on the observational data and to project future regional climate change over East Asia using ECHAM4/HOPE model and MM5 for downscaling. There are significant evidences on regional climate change in Korea, from several variables. The mean annual temperature over Korea has increased about 1.5∼$1.7^{\circ}C$ during the 20th century, including urbanization effect in large cities which can account for 20-30% of warming in the second half of the 20th century. Cold extreme temperature events occurred less frequently especially in the late 20th century, while hot extreme temperature events were more common than earlier in the century. The seasonal and annual precipitation was analyzed to examine long-term trend on precipitation intensity and extreme events. The number of rainy days shows a significant negative trend, which is more evident in summer and fall. Annual precipitation amount tends to increase slightly during the same period. This suggests an increase of precipitation intensity in this area. These changes may influence on growing seasons, floods and droughts, diseases and insects, marketing of seasonal products, energy consumption, and socio-economic sectors. The Korean Peninsular is located at the eastern coast of the largest continent on the earth withmeso-scale mountainous complex topography and itspopulation density is very high. And most people want to hear what will happen in their back yards. It is necessary to produce climate change scenario to fit forhigh-resolution (in meteorological sense, but low-resolution in socio-economic sense) impact assessment. We produced one hundred-year, high-resolution (∼27 km), regional climate change scenario with MM5 and recognized some obstacles to be used in application. The boundary conditions were provided from the 240-year simulation using the ECHAM4/HOPE-G model with SRES A2 scenario. Both observation and simulation data will compose past and future regional climate change scenario over Korea.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.163-163
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• 2003

The study area, Kwangneung Experiment Forest (KEF) is located on the west-central portion of Korean peninsula and belongs to a cool-temperate broadleaved forest zone. At the old-growth deciduous forest near Soribong-peak (533.1m) in KEF, we have established a permanent plot and a flux tower, and the site was registered as a KLTER site and also a KoFlux site. In this study, we aimed to present basic ecological characteristics and synthetic data of carbon budgets and flows, and some monitoring data which are essential for providing important parameters and validation data for the forest dynamics models or biogeochemical dynamics models to predict or interpolate spatially the changes in forest ecosystem structure and function. We made a stemmap of trees in 1 ha plot and analyzed forest stand structure and physical and chemical soil characteristics, and estimated carbon budgets by forest components (tree biomass, soils, litter and so on). Dominant tree species were Quercus serrata and Carpinus laxiflora, and accompanied by Q. aliena, Carpinus cordata, and so on. As a result of a field survey of the plot, density of the trees larger than 2cm in DBH was 1,473 trees per ha, total biomass 261.2 tons/ha, and basal area 28.0 m2/ha. Parent rock type is granite gneiss. Soil type is brown forest soil (alfisols in USDA system), and the depth is from 38 to 66cm. Soil texture is loam or sandy loam, and its pH was from 4.2 to 5.0 in the surface layer, and from 4.8 to 5.2 in the subsurface layer. Seasonal changes in LAI were measured by hemispherical photography at the l.2m height, and the maximum was 3.65. And the spatial distributions of volumetric soil moisture contents and LAIs of the plot were measured. Litterfall was collected in circular littertraps (collecting area： 0.25m2) and mass loss rates and nutrient release patterns in decomposing litter were estimated using the litterbag technique employing 30cm30cm nylon bags with l.5mm mesh size. Total annual litterfall was 5,627 kg/ha/year and leaf litter accounted for 61% of the litterfall. The leaf litter quantity was highest in Quercus serrata, followed by Carpinus laxiflora and C. cordata, etc. Mass loss from decomposing leaf litter was more rapid in C. laxiflora and C. cordata than in Q. serrata litter. About 77% of C. laxiflora and 84% of C. cordata litter disappeared, while about 48% in Q. serrata litter lost over two years. The carbon pool in living tree biomass including below ground biomass was 136 tons C/ha, and 5.6 tons C/ha is stored in the litter layer, and about 92.0 tons C/ha in the soil to the 30cm in depth. Totally more than about 233.6 tons C/ha was stored in DK site. And then we have drawn a schematic diagram of carbon budgets and flows in each compartment of the KEF site.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.15-15
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• 2003

In South Korea, marine terraces have been well developed along the eastern coastal zone, and previous researches on the marine terraces have also been focused on to this coastal zone. The marine terraces of the eastern coast of South Korea had been classified into three terrace groups, that is, the higher, middle, and lower surface ones, according to the heights of marine terraces by previous studies(Oh, 1981 ;Chang, 1987 ;Yoon et. al, 1999, 2003 ; Hwang and Yoon, 1996 etc.). Recently, however, it tends to classify the marine terraces based on the concept of geomorphic surface units(Lee, 1987 ; Kim, 1990 ; Choi, S. 2003; Choi S. et. al 2003a,b, etc). For example, it was proposed that the marine terrace surfaces of Eupcheon coast of the southeastern coastal area of Korea could be classified into 16 geomorphic surfaces, i.e., Eupcheon 1terrace(former shoreline height of 160m), 2(153m), 3(140m), 4(130m), 5(124m), 6(115m), 7(100m), 8(92m), 9(82m), 10(71m), 11(62m), 12(53m), 13(43m), 14(35m), 15(18m) and 16(10m) surfaces, in descending order, according to the former shoreline heights(Choi, S, 2003 ; Choi, S. et. al, 2003a,b). Among these terraces, Eupcheon 1, 2, 4, 5 and 7 surfaces had not been reported in previous works. Among the above mentioned marine terraces, Eupcheon 15 terrace, the most widely and continuously distributed marine terrace have been identified as marine terrace of the Last Interglacial culmination period(oxygen isotope stage 5e) which was based on amino acid dates(124∼125ka BP) and geomorphological features such as red soil, pollen analysis, fossil cryogenic structures and crossing terrace concept. Eupoheon 15 terrace surfaces have also been proposed as the key surface for the identification and correlation of the so-called '5e' marine terrace in the eastern coast of South Korea. This terrace was reconfirmed as the Last Interglacial culmination period, which was based on the identification of Ata tephra, one of the wide-spread marker tephra which indicates the Last Interglacial culmination period in Japan by Sasaki et. al(2002). It was thought that marine terraces of the eastern coast of South Korea had been formed by the steady-state uplifting during the Quaternary glacio-eustatic sea level changes(Choi, 1997). The uprift rate of 10cm/1,000years had been proposed in the eastern coast of South Korea based on the former shoreline altitude(18m) of the above Eupcheon 15 terrace. Therefore, it can be estimated that Eupcheon 1 terrace had been formed in the early Pleistocene from the above uprift rate. The OSL dating for the samples of Eupcheon 7, 9, 13, 15 and 16 terraces and identification of marker tephra in the terrace deposits are in progress. It is expected that more elaborate chronology on themarine terraces of the eastern coast of South Korea could be established by these absolute dates and marker-tephra.

• The Korean Journal of Quaternary Research
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• v.20 no.2
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• pp.51-57
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• 2006

Terrace stratigraphy of the southeastern coastal areas of Korea is reappraised on the basis of terrace mapping and geochronology. Coastal terraces are divided into uHT ($90{\sim}130\;m$), HT ($63{\sim}86m$), MT ($36{\sim}55\;m$), and LT ($8{\sim}25\;m$) according to altitude. Among these, the Lower Terrace I is interpreted to have formed during MIS 5e based on Tephras Aso-4 (MIS 5c), Ata(MIS 5d or 5e) and OSL data. The age of Lower Terrace II is thought to be MIS 5a based on tephras and OSL data. The uplift rate in the SE part of Korea during the formation of the Lower Terrace (i.e. the MIS 5) ranges from 0.08 to 0.25 mm/yr and averages as 0.15 mm/yr. Such value is quite small in comparison to that of Japan, Taiwan or many other tectonically active areas in the world.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.38-44
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• 2007

This paper describes the structural safety of solid fuel in the Hybrid Rocket Motor (HRM). Hybrid rocket combustion has the distinct regression characteristics which include the process of thermal pyrolysis and fuel vaporization. Most of all, this regression characteristics would structurally affect the strength of the fuel having a multi-port configuration, and even may cause the breaking from the fuel grain. This problem would probably influence the performance and operating safety of HRM. Therefore, for the safe operation of HRM, the critical port radius which determines the structurally safe region was discussed from the heat analysis of the solid fuel.