• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.88-88
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• 2023

• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.227-242
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• 1986

This paper describes the observed behavior in the direct shear test on decomposed granite soil having the complicate engineering properties at various different levels of factors. The objectives of this study were to investigate the characteristics of the decomposed granite soil under controlled various moisture content, dry density, strain rate and soaking which give influence to the shear strength. The results were summarized as follows; 1. The shear strength was decreased remarkably with the increasing of moisture contents of A and B soil were 5-10% and 15-20% respectively. 2. Cohesion and angle of internal friction were decreased with the increasing of moisture content and increased with the increasing of dry density. 3. The shear strength was increased with the increasing of normal stress and volume change was decreased on the whole. The shear strength was generally increased with the increasing of the strain rate. 4. As dry density increases, A-soil shows the progressive failure and the decrease of volume change while B-soil shows the initial failure and the increase of volume change. 5. The relationships between the soaked and unsoaked specimens were as follows ; ${\tau}_f=0.1009+1.026{{\tau}_f}^*$ (A-soil), ${\tau}_f=0.1586+0.8005{{\tau}_f}^*$ (B-soil) 6. Angle of internal friction of the direct shear test shows larger value than that of the triaxial compression test. All effective stress path was nearly similar.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.282-291
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• 1985

In order to investigate the settlement characteristics of fill dam with decomposed granite is used as a embankment material instead of conventional clay collected behavoir of Andong dam and analyzed. Andong dam is the use of decomposed granite in the embankment material, and various type of gauges were installed in dam to measure a pore pressure, interval vertical settlement, dam crest settlement, relative settlement, surface settlement and internal horizontal movement. The results were summerized as follows; 1. With the increase of embankment loading, the settlement of core zone during construction increased with linear and under the effective stress $7kg/cm^2$ vertical settlement ratio ranged between 0.1 and 0.8% approximately and showed smaller value than that of fill dam with clay were used as a embankment material. 2. Though embankment loading was increased with about over central part of embankment height, the settlement of core zone in the lower part of the embankment was influenced slightly. 3. Pore pressure responsed sensitively with the increase of coefficient of permeability in core zone and settlement increased with pore pressure were dispersed. 4. During construction relative settlement in the lower part of the embankment has the largest influence on magnitude of the relative density and after construction settlement showed larger value in the core zone which has the largest compression height. 5. Settlement distribution of dam crest showed larger value in the central part, maximum section of dam, but smaller value in near the abutment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.107-116
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• 1983

This paper is concerned with the permeability through a decomposed granite soil layer which is influnced by change of grain sizes and crushed soils made by varied compaction energy. The change in the content of crushed soils can be described in terms of the ratio of surface area ($S_w{^{\prime}}/S_w $). The experiments were carried out to obtain the relationships of the coefficient of permeability(K) versus the optimum moisture content($w_{opt}$) by the variable head permeability test with the samples that were preapared by compaction test. The results are found as follows; (1) By the change in compaction energy, the crush ratio increased whereas the void ratio decreased with a larger maximum dry density running in parallel with the zero air void curve. (2) The ratio of surface area was $0.33(P)^{0.96}$ in $S_w{^{\prime}}/S_w $ with no relation to the compaction energy. (3) The grain size which produced the largest crush of soil particles ranged from 0.5 to 1 millimetre (4) The relationship of K versus $e^3$/1+e appeared as a straight line on the full-log-scale paper under the optimum moisture state. (5) As the compaction energy was larger, the passing percentage of #200-sieve grains increased linearly. The increment in the surface area ratio was deemed to have been caused by the decreased in the permeability.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.229-234
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• 2007

To select the most proper soil for root initiation from stem cuts of Birdsfoot trefoil (Lotus corniculatus L.), eight-week-old stem cuts were cultured on three types of soil [commercial bed soil, decomposed granite (DCG), and river sand] for one month. The results showed that the root initiation ratios on DCG (77.8%) and river sand (70.0%) were relatively high, but the ratio on commercial bed soil (41.1%) was very low. To examine the effect of rare earth (RE) and Indole-3-Butyric Acid (IBA) on root initiation from stem cuts of Birdsfoot Trefoil, stem cuts were cultured on two types of soil (DCG and river sand) with treatment of RE and IBA for one month. The root initiation ratios turned out to be 90.0% (DCG with 60 ppm of RE), 80.0% (river sand with 20 ppm of RE), 96.7% (DCG with 40 ppm of IBA), and 96.7% (river sand with 40 ppm of IBA). These results suggested that the most efficient way for root initiation of Birdsfoot trefoil was to culture the stem cuts on river sand or DCG over 30 days with IBA treatment (40 ppm).

• Horticultural Science & Technology
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• v.33 no.1
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• pp.24-30
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• 2015

This study was conducted to select proper light intensity, pot media, and fertilization level for potted Hepatica asiatica Nakai native to Korea. The plants were grown under various light intensities (shading rate, 52, 82, 90, 97%) imposed by shading net. Plants grown with 52% shading showed a low survival rate (65%). Survival rate increased as shading increased, with over 80% survival in shading above 90%. Growth indexes such as fresh weight and leaf number did not show any significant difference between shading treatments. Plants grown in a soil mixture of decomposed granite:fertilizer-amended media:Kanumatsuchi (60:10:30, v/v/v) or river sand:fertilizer-amended media:bark (50:20:30) showed over 85% survival. However, plants grown in a soil mixture of river sand:fertilizer-amended media:Kanumatsuchi (50:30:20) or upland:river sand (40:60) showed very low survival, below 60%. Leaf number and plant height were the highest in a soil mixture of decomposed granite:fertilizer-amended media:Kanumatsuchi (60:10:30) as well. To select a proper fertilization level for H. asiatica, hyponex solution diluted 1,000- or 2,000-fold were applied weekly or biweekly. The survival rate was lowest at weekly application with 1,000-fold diluted solution, and no significant difference was observed between other treatments. In conclusion, H. asiatica exhibits preferences for very low light intensity and soil with air permeability, and is adaptable to a broad range of fertilization levels.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.31-38
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• 2019

Recently, there has been an increasing number of ground subsidence (sink-hole) in the downtown areas, and in such a case, it is important to minimize accidents and passages through prompt recovery. With respect to the present recovery method for ground subsidence, the methods of applying the back filling after excavating the ground subsidence or using the grouting injected materials to restore the ground are mostly used, but there has been few studies on materials used for recovering the ground subsidence. Therefore, in order to clarify the characteristics of back filling materials used in the ground subsidence, this study uses the environment-friendly hardening agent to improve the dredged clay, and then, the mixture ratio of hardening agent and mixture ratio of decomposed granite soil is changed to cure for 3, 7, 14 and 28 days to analyze the intensity characteristics of the unconfined compression, and it was compared with the unconfined compression intensity for the previously used cement, a hardening agent. In order to evaluate the characteristics of intensity on the back filling materials, the C.B.R test was carried out, and for the review on whether the back filling materials influence on corrosion of water and sewer pipes and others, the soil non-resistance test was carried out. As a result of the test, for the case of the recovery work of the ground subsidence that requires urgency, it is considered as prudent if the hardening agents of 12% are integrated to cure for 3 days or longer, and for not having the influence on the corrosion of the gas tube or water pipes, it is proposed to mix for 30% or more of the decomposed granite soil. Door model test were conducted To confirm the bearing capacity characteristics of the solidified layer.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.43-43
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• 2019

Deparia pycnosora (Christ) M. Kato is a fern used as ornamental plant. In addition, it is called "Teol-go-sa-ri" in Korean name. The aim of this study was to develop a practical propagation method of D. pycnosora using tissue culture technique. Prothallus obtained from spore germination was the used as experiment materials. The prothalli (300 mg) used in all experiments were sub-cultured for 8-week intervals. The most suitable media for prothallus propagation were identified by culturing 300 mg of prothalli in $1/4{\times}$, $1/2{\times}$, $1{\times}$, $2{\times}$ MS medium and in Knop medium for 8 weeks. Also, the prothalli were cultured by chopping with a scalpel. In addition, sucrose, activated charcoal, and total nitrogen source were added in different concentrations based on the culture medium selected. Cultures were maintained at a temperature of $25{\pm}1^{\circ}C$, light intensity of $30{\times}1.0{\mu}mol-m-2{\cdot}s-1$, and a photoperiod of 16/8 h (light/dark) in in vitro. The results showed that optimum was achieved prothallus fresh weight and development in $1{\times}$ MS medium. When other components were added to the basic $1{\times}$ MS medium, prothallus propagation was maximized in $1{\times}$ MS medium supplemented with 2% sucrose, 0.2% activated charcoal, and 60 mM total nitrogen. To select a suitable soil mixture for sporophyte formation, 1.0 g of prothallus was blended with distilled water, spread on five combinations of different soil substrates (decomposed granite, horticultural substrates, peat moss, and perlite), and cultivated for 12 weeks. The sporophyte cultures were maintained at a temperature of $25{\pm}1^{\circ}C$, light intensity of $43{\pm}2.0{\mu}mol-m-2{\cdot}s-1$, humidity of $84{\pm}1.4%$, and a photoperiod of 16/8 h (light/dark). As a results, horticultural substrate alone, 2:1 (v:v) mixtures of horticultural substrate and perlite, and 2:1 mixtures of horticultural substrate and decomposed granite induced 208.0, 201.3 and 248.8 sporophytes per pot, respectively. Therefore, this result could provide a practical mass propagation method of D. pycnosora

• Journal of Plant Biotechnology
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• v.46 no.2
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• pp.119-126
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• 2019

This study was conducted to investigate the optimal culture method for gametophyte and sporophyte propagation in Coniogramme japonica (Thunb.) Diels, which can be used in various fields. The propagation of prothallus were cultured in 1/4 - 1 Murashige and Skoog medium and Knop medium for 10 weeks. The results indicated that the fresh weight of prothallus was the highest (14.5 g) in 1MS medium. Subsequently, various concentrations of sucrose, activated charcoal and nitrogen source were also added to 1MS medium and cultured for 8 weeks. The results provided that the sucrose concentration was 3% and the fresh weight of prothallus was the highest 10.8 g. According to the concentration in the range of 8.8 ~ 10.8 g, in the case of activated charcoal, the four treatments showed no significant difference. The nitrogen source was added at a concentration of 30, 60 and 120 mM with the ratio of ${NH_4}^+:{NO_3}^-$ being 1 : 2. As a result, the fresh weight of all treatments increased to similar level but there was no significant difference. We investigated sporophyte formation according to soil type and the highest number of sporophytes at 228.0 was formed in soils mixed with horticultural substrate and decomposed granite at 2 : 1 (v : v). On the other hand, sporophyte was not formed in soils containing peatmoss except for the one with peatmoss and decomposed granite at 2 : 1 (v : v).

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.183-194
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• 2002

Biotite and its weathering Products in the weathering Profile of Andong granite were examined using X-ray diffraction, chemical analysis, and electron microscopy. Major weathering product of biotite was oxidized biotite, which is decomposed into kaolinite in the upper part. Discrete vermiculite or hydrobiotite was not detected although minor vermiculite (5%) was randomly interstratified with oxidized biotite. Excess positive charge induced by iron oxidation was balanced by release of Fe (16%) and Mg (12%) from octahedral site and K (13%) from interlayer site. After slight chemical and structural modification induced by iron oxidation, oxidized biotite persists through the weathering profiles with partial decomposition in the upper part of the profile. Formation environments and dissolution experiments of oxidized biotite highly resistant to weathering are required to understand the elemental behavior in the surface environments on the biotite-bearing bedrocks.