• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.131-144
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• 1980

The Linear Regression Model to extend the monthly runoff data in the short-recorded river was proposed by the author in 1979. Here in this study generalization precedure is made to apply that model to any given river basin and to any given station. Lengthier monthly runoff data generated by this generalized model would be useful for water resources assessment and waterworks planning. The results are as follows. 1. This Linear Regression Model which is a transformed water-balance equation attempts to represent the physical properties of the parameters and the time and space varient system in catchment response lumpedly, qualitatively and deductively through the regression coefficients as component grey box, whereas deterministic model deals the foregoings distributedly, quantitatively and inductively through all the integrated processes in the catchment response. This Linear Regression Model would be termed "Statistically deterministic model". 2. Linear regression equations are obtained at four hydrostation in Geum-river basin. Significance test of equations is carried out according to the statistical criterion and shows "Highly" It is recognized th at the regression coefficients of each parameter vary regularly with catchment area increase. Those are: The larger the catchment area, the bigger the loss of precipitation due to interception and detention storage in crease. The larger the catchment area, the bigger the release of baseflow due to catchment slope decrease and storage capacity increase. The larger the catchment area, the bigger the loss of evapotranspiration due to more naked coverage and soil properties. These facts coincide well with hydrological commonsenses. 3. Generalized diagram of regression coefficients is made to follow those commonsenses. By this diagram, Linear Regression Model would be set up for a given river basin and for a given station (Fig.10).

• Journal of Ginseng Research
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• v.32 no.3
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• pp.194-209
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• 2008

This study is for major element relationships between ginsengs and soils from three representative soil types from Keumsan, shale, phyllite and granite. In the weathered soils, the granite and phylllite are high while the shale are low. The granite show distinctive positive and negative relationships rather than the phyllite and shale. In the field soils, the granite and phyllite are high while the shale are low. Positive relationships are distinctive with the increasing ages, and in the granite. In the ginsengs, high element contents are shown in K and Na of the shale, Mg and Ca of the phyllite, and Al, Mn and Ti of the granite. In the same regions, the 2 and 3 years are mainly low, but high in the 4 year. Positive correlations are distinctive in the 2 and 4 year of the shale, and 3 year of the granite. Comparisons with ginsengs of the same ages from the different areas suggest that the granite show high element contents with the ages. It also suggests that the 2 year of the granite, and 3 and 4 year of the shale and phyllite are high. Relative ratios(weathered/field soils) among the soils suggest that the weathered are generally high, especially in the granite rather than the shale. Relative ratios between field soils and ginsengs(field soils/ginseng) suggest that the soils are higher than the ginsengs, and differences of several hundred times in the Al and Ti, and of several ten times in the Mn are shown between two. Comparisons among the different ages from the same areas suggest that differences of several hundred times in the Al and Ti are shown. It suggests that ginseng contents are significantly different from the field soils in the Al and Ti contents. Comparisons among from the same ages of the different areas suggest that high element differences are shown in Na of the shale, and Mn of the phyllite, while low element differences are found in Mg of the shale, and Al, Mn, and Na of the granite.

• The Korean Journal of Mycology
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• v.3 no.1
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• pp.1-19
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• 1975

Since the importance of casing in fruit body formation of Agaricus bisporus has been emphasized, physico-chemical characteristics of casing materials were discussed by many workers and a mixture of peat and mineral soil as proper casing material has been adopted in many of mushroom growing countries. Because of limited resources of peat in Korea, it is necessary to find practical performance and substitutional materials for casing. The effect of casing on mycelial growth and mushroom yield of A. bisporus varied with materials, its combination and practices etc. The experiments to be discussed in this paper are concerned with pH and Ca of casing material which influence A bisporus, and changes of physico-chemical characteristics with mixing ratio of casing materials and its effect on A. bisporus. The optimum range of moisture content of each material, management of watering and application of physico-chemical characteristics casing materials was also investigated and re-use of weathered spent compost for casing material was described. 1. The effect of calcium on mycelial growth of A. bisporus at various pH in Halbschalentest showed different results with calcium sources. Best results were obtained around neutrality and fresh weight of fruit bodies grown in the range of pH 7 to 8 was highest among the tested levels. 2. Available moisture, pore space, organic matter, cation exchangeable capacity and exchangeable cation was increased by an increase of mixing ratio of peat in casing materials, while an adverse effect was obtained by addition of sand. 3. Mycelial growth on clay loam was more rapid at a lower bulk density of 0.75g/cc and at 20% moisture content on a dry weight basis at the same bulk density. 4. Mixing ratio of casing materials, 60 to 80 per cent by volume of peat mixed with 20 to 40 per cent of clay loam produced the highest yield of fresh fruit bodies and sand the lowest. However, per cent of open cap was highest in peat and lowest in sand. 5. Days required for fruit body initiation was shortened in mixtures of peat and clay loam by one to three days compared with other materials and the formation of flushes was clear. 6. The effect of some physico-chemical characteristics of casing materials on the fresh weight of fruit bodies were estimated by a multiple regression equation; Y=-923.86+$8.18X_1+8.04X_2+7.90X_3+0.12X_4+2.03X_5-0.82X_6-0.54X_7$ where $X_1,X_2,X_3,X_4,X_5,X_6,X_7$ are sand, silt, clay, available moistuer, porosity, organic matter and exchangeable cation respectively. The productivity of certain casing material could be predicted from this equation. 7. Fresh weight of fruit bodies was positively correlated with porosity exchangeable cation, organic matter, available moisture, silt and clay of materials; while sand was negatively correlated. On the contrary, sand was the unique factor reducing per cent of open cap. 8. Distribution of three phases of high productive casing material was concentrated in the range of 10 to 30 per cent solids, 15 to 30 per cent liquids, and 50 to 60 per cent in air volume. 9. Fresh weight of fruit bodies from peat was not affected with heavy watering but in clay loam and sandy loam severe crop losses occurred. Fresh weight of individual fruit was increased and open caps were decreased with heavy watering but light watering resulted in adverse effects: its effect was especially great in peat. 10. Optimum range of moisture content by weight on a dry basis was different with each casing material. To maintain optimum moisture content concerned with yield of fruit bodies and open cap, sandy loam and peat mixtures required daily watering of 0.6, 0.6 to 1. 2 and 1.2 to 2.4 liters per $3.3m^2$ of bed area, respectively. 11. Maximum yield of fruit body was recorded in the range of pF 2. 0 to 2. 5 of casing materials if organic matter content was below 4.2 per cent and in pF 1. 3 to 1.8 if above 7.1%. 12. pF curve of a certain casing material could be draws from moisture content at various pF values by multiple regression equations provided texture, organic matter and calcium of the casing material are given. Optimum moisture range of the casing materials also could be estimated by the equation. 13. It was possible to improve the phyico-chemical characteristics of clay loam and sandy loam by addition of weathered spent compost although the effect was less than in the case of peat. Fresh weight of fruit bodies wsa increased by addition of weathered spent compost but its effect was not as remarkable as peat. Accordingly, further studies will be required.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.199-211
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• 1994

Butachlor applied pre-emergence at 3.6kg ai/ha inhibited the growth and developments of shoot of barnyardgrass under dry condition, whereas rice was unaffected. Growth of rice and barnyardgrass under water condition was severely inhibited by treatment of butachlor but that of transplanted rice was not affected. The inhibition rate was higher under water condition, in broadcast rice and direct seeded rice than under dry condition, drilled rice and transplanted rice, respectively. The major anatomical response of stem of barnyardgrass seedling to butachlor under dry condition were partial reduction in thickness and collapse of leaf sheath, while not in rice. Broadcast rice on soil under water condition appeared reduction and constriction of leaf primordia thickness, and barnyardgrass formed tubular-like leaves and showed inhibited elongation of apical meristem. On the other hand, transplanted rice did not show these responses.

• Journal of Life Science
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• v.25 no.6
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• pp.680-685
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• 2015

Previously, cellulase and xylanase producing microorganism, Bacillus subtilis NC1, was isolated from soil. Based on the 16S rRNA gene sequence and API 50 CHL test the strain was identified as Bacillus subtilis, and named as B. subtilis NC1. We cloned and sequenced the genes for cellulase and xylanase. Plus, the deduced amino acid sequences from the genes of cellulase and xylanase were determined and were also identified as glycosyl hydrolases family (GH) 5 and 30, respectively. In this study to optimize the medium parameters for cellulase production by B. subtilis NC1 the RSM (response surface methodology) based on CCD (central composite design) model was performed. Three factors, tryptone, yeast extract, and NaCl, for N or C source were investigated. The cellulase activity was measured with a carboxylmethyl cellulose (CMC) plate and the 3,5-dinitrosalicylic acid (DNS) methods. The coefficient of determination (R²) for the model was 0.960, and the probability value (p=0.0001) of the regression model was highly significant. Based on the RSM, the optimum conditions for cellulase production by B. subtilis NC1 were predicted to be tryptone of 2.5%, yeast extract of 0.5%, and NaCl of 1.0%. Through the model verification, cellulase activity of Bacillus subtilis NC1 increased from 0.5 to 0.62 U/ml (24%) compared to the original medium.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.136-142
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• 2016

Lespedeza species are mainly used for wildlife food and cover and for erosion control. The germination of these species can be enhanced after a fire occurrence in forest, which is known as fire-activated seeds to germinate. While the heat treatment could break seed dormancy of Lespedeza, its germination rate was quite low. We investigated that chemical scarification could promote germination of L. tomentosa. Seeds were soaked in 100% sulfuric acid (H₂SO₄) for 0, 1, 3, 6, 12, 24, 48, 96, 192, and 384 min, and then washed in distilled water for 24 h. Very few seeds were germinated in control (H₂SO₄ for 0 min). More than 90% of seeds were germinated in H₂SO₄ for 24, 48, and 92 min. However, some damage was observed in roots and cotyledons of seedling dipped in H₂SO₄ for a long time. To search the optimal soaking time in H₂SO₄ without defects, seeds scarified in H₂SO₄ for 30, 60, 90, 120, 150, 180, and 300 min were sown the commercial soil medium. Seeds treated with H₂SO₄ for 90 min and 150 min emerged by about 92% and 84%, respectively. Therefore, H₂SO₄ treatment could break the seed dormancy of Lespedeza species, and especially in case of L. tomentosa the optimal treatment time in sulfuric acid was one to two hours. Germination of L. tomentosa began promptly following the scarification and was completed within about one month, indicating that seeds has no physiological dormancy, just has physical dormancy.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.61-72
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• 2014

To present a guideline on the construction and management of artificial wetlands for high biomass production, three emergent macrophytes (Phragmites australis, PA; Typha angustifolia, TA; and Zizania latifolia, ZL) were planted under two substrates conditions (general soil with and without moss peat) and two water levels (5 cm and 20 cm) and monitored for three years. ZL showed greater growth performance rather than the others not only at early growth phase in the first year [shoot height, 200 cm; above-ground dry weight (AGDW), 500 $g/m^2$] but also in the last year (ZL, 1,100 $g/m^2$; TA, 770 $g/m^2$; and PA, 450 $g/m^2$ of AGDW). ZL with rapid growth at the early growth phase was not affected by naturally introduced weeds, whereas slower and poorer growth of PA and TA at the early growth phase resulted in relatively higher introduction and establishment of natural weeds. In turn, such introduced weeds negatively contributed to the growth of PA and TA particularly under shallow water (5 cm) with the substrate condition including moss peat. We suggest a plant material with rapid and great growth at the early phase such as ZL for reducing possible negative influences by the natural weeds and wild animals for high biomass production in constructed wetlands. A pre-growing process in greenhouse prior to planting might be an useful option to raise the competitiveness of those species when planting PA and/or TA. In addition, we recommend that integrated weed management system with utilizing various options at the most appropriate timing must be applied for maintaining sustainable high biomass production at the artificial wetlands.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.301-307
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• 1996

The experiment was conducted to clarify the effect of water stress treatment on growth character of Ligusticum chuanxiong Hort. The water stress treatment was imposed artificially on seedling, flowering and rhizome enlargement stage of the plant. The decrease ratio of leaf area compare with control decreased to 24.4% by water stress treatment at seedling stage and to 41.6% at rhizome enlargement stage. The reduction rate of chlorophyll content at the end of water stress treatment was 41.2% at the see­dling stage and no difference at the flowering stage. The chlorophyll content of water stress treatment on seedling and flowering stage was recovered to 95% at harvest time. The ratio of rootlet distribution from top soil to l0cm depth showed maximum to 90% at the seedling stage and to 20cm depth showed max­imum to 6.4% at the rhizome enlargement stage. The dry weight of rootlet was decreased to $19.3{\sim}40.3%$ by water stress treatment. Dry weight of aerial part and underground part of the plant decreased in the order of seedling, flowering, rhizome enlargement and control and the dry weight of aerial part decrease more severely than underground part.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.425-434
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• 2008

Arsenic contamination in soil and groundwater has recently been one of the most serious environmental concerns. This arsenic contamination can be originated from natural or anthropogenic sources. It has been well known that arsenic behavior in geo-environmental is controlled by various oxides or hydroxides, such as those of iron, manganese, and aluminum, and clay minerals. Among those, particularly, iron (oxy)hydroxides are the most effective scavengers for arsenic. For this reason, this study characterized arsenic adsorption of magnetite which is a kind of iron oxide in nature. The physicochemcial features of the magnetite were investigated to evaluate adsorption of arsenite [As(III)] and arsenate [As(V)] onto magnetite. In addition to experiments on adsorption equilibria, kinetic experiments were also conducted. The point of zero charge (PZC) and specific surface area of the laboratory-synthesized magnetite used as an arsenic adsorbent were measured 6.56 and $16.6\;g/m^2$, which values seem to be relatively smaller than those of the other iron (oxy)hydroxides. From the results of equilibria experiments, arsenite was much more adsorbed onto magnetite than arsenate, indicating the affinity of arsenite on magnetite is larger than arsenate. Arsenite and arsenate showed adsorption maxima at pHs 7 and 2, respectively. In particular, adsorption of arsenate decreased with increase in pH as a result of electrical repulsion caused by anionic arsenate and negatively-charged surface of magnetite. These results indicate that the surface charge of magnetite and the chemical speciation of arsenic should be considered as the most crucial factors in controlling arsenic. The results of kinetic experiments show that arsenate was adsorbed more quickly than arsenite and adsorption of arsenic was investigated to be mostly completed within the duration of 4 hours, regardless of chemical speciation of arsenic. When the results of kinetic experiments were fitted to a variety of kinetic models proposed so far, power function and elovich model were evaluated to be the most suitable ones which can simulate adsorption kinetics of two kinds of arsenic species onto magnetite.

• Journal of the Mineralogical Society of Korea
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• v.26 no.2
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• pp.101-110
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• 2013

Due to the large specific surface area and great reactivity toward environmental contaminants, nanocrystalline mackinawite (FeS) has been widely applied for the remediation of contaminated groundwater and soil. Furthermore, nanocrystalline FeS is rather thermodynamically stable against anoxic corrosion, and its reactivity can be regenerated continuously by the activity of sulfate-reducing bacteria. However, nanocrystalline mackinawite is prone to either spread out along the groundwater flow or cause pore clogging in aquifers by particle aggregation. Accordingly, this mineral should be modified for the application of permeable reactive barriers (PRBs). In this study, coating methods were investigated by which mackinawite nanoparticles were deposited on the surface of alumina or activated alumina. The amount of FeS coating was found to significantly vary with pH, with the highest amount occurring at pH ~6.9 for both minerals. At this pH, the surfaces of mackinawite and alumina (or activated alumina) were oppositely charged, with the resultant electrostatic attraction making the coating highly effective. At this pH, the coating amounts by alumina and activated alumina were 0.038 and 0.114 $mmol{\cdot}FeS/g$, respectively. Under anoxic conditions, arsenite sorption experiments were conducted with uncoated alumina, uncoated activated alumina, and both minerals coated with FeS at the optimal pH for comparison of their reactivity. Uncoated activated alumina showed the higher arsenite removal compared to uncoated alumina. Notably, the arsenite sorption capacity of activated alumina was little changed by the coating with FeS. This might be attributed to the abundance of highly reactive hydroxyl functional groups (${\equiv}$AlOH) on the surface of activated alumina, making the arsenite sorption by the coated FeS unnoticeable. In contrast, the arsenite sorption capacity of alumina was found to increase substantially by the FeS coating. This was due to the consumption of the surface hydroxyl functional groups on the alumina surface and the subsequent occurrence of As(III) sorption by the coated FeS. Alumina, on the surface area basis, has about 8 times higher FeS coating amount and higher As(III) sorption capacity than silica. This study indicates that alumina is a better candidate than silica for the coating of nanocrystalline mackinawite.