• Journal of Ginseng Research
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• v.9 no.1
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• pp.36-41
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• 1985

The study was conducted to investigate the changes of soil physico-chemical properties between soils of preplanting fields and 2 years old ginseng fields, and compare the missing plant rate among the 2 years 016 ginseng fields. 1, The missing plant rate of 2 years old ginseng was high in sand loam while low in clay loam soil texture, soil porosity and NO3-N were remarkably increased in 2 years old ginseng field than preplanting soil, as the clay content was increased, soil porosity seemed to be increased but exchangeable nitrogen decreased. 2. The preplanting soil management methods did not significantly influenced on the missing plant rate and soil porosity in 2 years old ginseng fields, However NO3-N content and Fusarium density seemed to be decreased as the plow frequency was increased, exchangeable nitrogen content, whereas, seemed to be increased with more organic matter. 3. Differences of clay content (below 15% and above 20% of clay content) was significantly influenced on soil porosity, bulk density, total nitrogen, organic matter and P2O5 content. 4, Missing rate showed negative correlation with clay, soil moisture, and organic matter content but positive corelation with NO3-N in 2 years old ginseng fields.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.749-758
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• 2017

This Research was the standardization of nutrient sources by reviewing the possibility of cultivation and analysis of imported nutrient sources used in Pleurotus ostreatus culture. As a first result, the concentration of heavy metals was not detected or trace, and the total nitrogen content of cotton seed pomace was 6.22% in Australia, which was higher than that of Chinese or USA. As a second result of physical properties of nutrient sources, the water holding capacity of beet pulp from Egypt was higher with increasing pressure. The volume water content of US was highest at 400hpa and 500hpa in case of cottonseed meal. Third, the content of total nitrogen was the highest at pH 5.51 and the total nitrogen content was the highest at 2.45, and the C/N ratio was the highest at 28.18. Last result shows that first germination day, yield and biological effciency of all treatments were not significant differnet except T2. These results shows that australian cootton was inappropriate to Pleurotus ostreatus culture. Nevertheless, the safety and standardization of the Pleurotus ostreatus culture medium should be assured by reviewing the media low material importing season, mushroom yield and nutrient sources.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.134-141
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• 2000

The person' spending time in underground s[aces within indoor environment show a tendency to increase every year, but in Korea, levels and sources of pollutant in underground spaces have not been well-characterized. Therefore, as part or a larger indoor environmental study, conducted at subway station in Seoul, nitrogen dioxide was measured using passive samplers in 16 subway stations, 2 tunnels and 70 workers of subway station. The mean concentrations of nitrogen dioxide in subway stations were $27.87{\pm}7.15$ ppb at station office, $35.76{\pm}8.35$ ppb at platform, $52.60{\pm}13.04$ ppb at outdoor, respectively, and the Indoor/Outdoor ratio were 0.49~0.93. The mean concentrations of nitrogen dioxide in tunnels were $44.91{\pm}4.67$ ppb in Chunggye-Nowon tunnel with a single track, $42.55{\pm}3.33$ ppb in Mokkol-Taenung tunnel with double track, respectively, and as a result of t-test, a single track levels were higher than double track levels(p<0.05). The mean personal exposure of the subject of station workers was $29.40{\pm}9.75$ ppb.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.33-37
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• 1992

Napier grass (Pennisetum purpureum Schum.) harvested at an early growth stage was ensiled with 4% of molasses in a polyethylene bag silo which contained 15 kg of chopped forage each. Dry matter (DM) content of the silage was so low as 14.75%, although chemical quality of the silage was very high. Ratio of ammonia nitrogen to total nitrogen was 6.59%, and the pH value of the silage was 3.79. Nutritive value of the silage was estimated using goats and compared to that of a timothy hay as a reference ration. Feeding level of each rations was adjusted to a level of nitrogen (N) recommendation. DM and N digestibilities of the silage were 65.0 and 54.5%, respectively, but those of the timothy hay were 37.6 and 37.2%. Feeding of the napier grass silage maintained body weight and kept positive N retention. Ammonia N concentration in the rumen fluid in goats fed the napier grass silage increased after feeding, but blood urea concentration was constant. Feeding of the timothy hay did not increase ammonia N concentration in the rumen fluid, but increased blood urea concentration. These facts indicated that the napier grass silage had enough digestible DM and N for maintenance ration to goats.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.2
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• pp.95-102
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• 2003

To get the informations of quality uniformity of threshed burley tobacco produced from 1997 to 2001 and processed at various leaf processing factories, chemical constituents contents and coefficient of variation(C.V.) were analysed. The average chemical constituents contents of 12 grades during 5 years ranged as follows; nicotine 1.76～2.66%, total nitrogen 4.15～4.80%, crude ash 21.6～22.4% and chlorine 1.08～1.20%. The variations of chemical constituents contents among crop years was higher in nicotine while lower in crude ash. The nicotine content of upper leaves were influenced negatively by rainfalls, while total nitrogen content were influenced positively by air temperature and sunshine hours during July. The C.V. of chemical content in same grade was higher in chlorine and nicotine while lower in crude ash. The ratio of C.V. among leaf tobacco processing factories/C.V. of total sample in same grade was high in nicotine. To reduce the C.V. of chemical constituents, it is recommendable to thresh the leaf tobacco at one processing factory. When the leaves being processed at one factory, the decreasing effect of deviation was higher in nicotine, particularly.

• Journal of Embryo Transfer
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• v.14 no.2
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• pp.83-88
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• 1999

This study was undertaken with three objectives : to determine the optimal time of blood collection for plasma urea nitrogen(PUN) analysis, to examine the frequency distribution of PUN levels in recipient herd and to relate concentration of PUN to conception rate in Hanwoo recipients. The relationship between PUN level and time postfeeding was examined for 5 individual cows. Mean concentration of PUN rose for 4hrs postfeeding and decreased to PUN level before feeding at 10hrs postfeeding. And then, the blood for PUN analysis was collected at the time before feeding in next experiments. The ratio of cows with PUN concentration of < 12, 12∼18 and 18mg/dl were 50.6, 39.9 and 9.5% in 163 recipients, individually. The pregnancy rate of cows with PUN concentration 12∼16 mg/dl (63.3%) was higher than that of cows with PUN concnetration < 12 mg/dl (46.7%) or > 16mg/dl (42.9%). There results suggest that the PUN test may be beneficial for management of recipient herd in effects to maintain or improve reproductive efficiency.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.1
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• pp.20-26
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• 2003

To investigate the effects of reduction of leaf processing factories on the uniformity of processed leaf quality, the contents and their C.V.(Coefficient of Variation) of chemical constituents of flue-cured leaf tobacco produced from 1997 to 2001 and processed at various factories were analysed. The average leaf chemical contents of 12 grades for 5 years ranged as follows ; nicotine 2.00∼0.85%. total sugar 10.7∼16.9%, total nitrogen 2.36∼2.78%, crude ash 14.6∼15.6% and chlorine 0.50∼0.75%. The variations of chemical contents among crop years was higher in total sugar content while lower in crude ash content. The C.V. of chemical content in same grade leaves was higher in chlorine content while lower in total nitrogen and crude ash contents, and the ratio of C.V. among processing factories/C.V. in total population was higher in total sugar content while lower in crude ash content. When the leaves were processed at one factory, the deviations of chemical contents reduced considerably. Particularly, the decreasing effect of deviation was higher in total sugar content.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.348-355
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• 2002

To know characteristics of water quality in Saemankeum area, we were investigated the water quality of surface layer from July of 1999 to June of 2000. The concentrations of COD and chlorophyll a were in the range of $0.64\~6.40$ (mean 1.96)mg/L, $1.95\~51.55$ (mean 11,07)$mg/m^3$, respectively. The annual mean concentrations of DIN, DIP were found to be 21.182 $\mu$g-at/L and 0,655 $\mu$g-at/L respectively, which were exceeding second grade of seawater quality standard. The nitrogen ratio to the phosphorus was lower than 1. Therefore, nitrogen was playing an important role in phytoplankton growth as limiting factor in study area. Mean values of eutrophication index were exceeding 1, which was the eutrophication criteria. Especially Mankyung and Dongjin estuary were shown over 10 as eutrophication index. Therefore, Saemankeum area could be evaluated to possibility area for eutrophication. Released rate for ammonia nitrogen and phosphate phosphorus from sediments were 62.92 ${\mu}g-at/m^3/hr$ and 6.71 ${\mu}g-at/m^3/hr$, respectively.

• Membrane and Water Treatment
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• v.9 no.4
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• pp.263-271
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• 2018

The objective of this work was to analyze organic matter removal, nitrification, biomass growth and membrane fouling in a submerged flat-sheet membrane bioreactor, fed with synthetic wastewater, of similar composition to the effluents generated in a fish meal industry. After biomass acclimatization with saline conditions of 12 gNaCl/L and COD/N ratio of 15 in the bioreactor, results showed that the organic matter removal was higher than 90%, for all organic loading rates (0.8, 1, 1.33 and $2gCOD/L{\cdot}d$) and nitrogen loading rates (0.053, 0.067, 0.089 and $0.133gN/L{\cdot}d$) tested during the study. However, nitrification was only carried out with the lowest OLR ($0.8gCOD/L{\cdot}d$) and NLR ($0.053gN/L{\cdot}d$). An excessive concentration of organic matter in the wastewater appears as a limiting factor to this process' operating conditions, where nitrification values of 65% were reached, including nitrogen assimilation to produce biomass. The analysis of membrane fouling showed that the bio-cake formation at the membrane surface is the most impacting mechanism responsible of this phenomenon and it was demonstrated that organic and nitrogen loading rates variations affected membrane fouling rate.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.34-40
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• 2013

Various depositional conditions, such as substrate, pressure, deposition time, temperature of substrate, power and gas composition, have mainly been studied to attain DLC films using RF sputtering system up to the current. In this study, the $N_2/Ar/CH_4$ gas mixture factored on characteristics of DLC deposited film such as structure, hardness, electrical property were investigated. The concentration of the $N_2$ gas in the sputtering gas may be a significant effect on the growth rate of the doped films, because nitrogen ions react not only with the carbon atoms on the target but also with $C_xH_y$ ions in the plasma on the substrate surface. It was seen from this experimental that the resistance of deposited film is decreased, and the relative intensity ratio of D to G peak is increased as nitrogen content of film deposition is increased.