• Geomechanics and Engineering
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• v.30 no.5
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• pp.401-411
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• 2022

To obtain the dynamic mechanical properties, fracture modes, energy and brittleness characteristics of Furong Baijiao coal rock, the dynamic impact compression tests under 0, 4, 8 and 12 MPa confining pressure were carried out using the split Hopkinson pressure bar. The results show that failure mode of coal rock in uniaxial state is axial splitting failure, while it is mainly compression-shear failure with tensile failure in triaxial state. With strain rate and confining pressure increasing, compressive strength and peak strain increase, average fragmentation increases and fractal dimension decreases. Based on energy dissipation theory, the dissipated energy density of coal rock increases gradually with growing confining pressure, but it has little correlation with strain rate. Considering progressive destruction process of coal rock, damage variable was defined as the ratio of dissipated energy density to total absorbed energy density. The maximum damage rate was obtained by deriving damage variable to reflect its maximum failure severity, then a brittleness index BD was established based on the maximum damage rate. BD value declined gradually as confining pressure and strain rate increase, indicating the decrease of brittleness and destruction degree. When confining pressure rises to 12 MPa, brittleness index and average fragmentation gradually stabilize, which shows confining pressure growing cannot cause continuous damage. Finally, integrating dynamic deformation and destruction process of coal rock and according to its final failure characteristics under different confining pressures, BD value is used to classify the brittleness into four grades.

• Journal of the Korean Wood Science and Technology
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• v.51 no.6
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• pp.542-554
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• 2023

This study is a continuation of our previous work, which focused on the resistance of jabon wood to termites after impregnation with wood vinegar (WV) and animal-based adhesive (kak). This paper presents the physicomechanical properties of fast-growing jabon wood impregnated with kak at two concentrations (8% and 10%) in wood vinegar or water as a solvent with and without 4% borax. The physical properties of the impregnation solution, that is, viscosity, density, pH, and solid content, were evaluated according to SNI 06-4567-1998. Some physical parameters, such as weight percent gain (WPG), density, water uptake, anti-swelling efficiency (ASE), crystallinity, and mechanical properties, i.e., modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength parallel to the grain (CS), of the impregnated wood were determined. Based on these results, wood impregnated using a mixture of kak in WV presented better physical (increased WPG, density, dimensional stability, and crystallinity) and mechanical (increased MOE/MOR and compression strength) properties than wood impregnated with a water solvent or untreated wood. The wood impregnated using WV and water solvent improved the physical and mechanical properties. The density of the wood increased by 44%-58% and 32%-47%, ASE radial-tangential increased by 38%-45%; 15%-28% after 24 h of water immersion, crystallinity increased by 59%-74%; 36%, MOE increased by 46%-57%; 28%-31%, MOR increased by 29%-34%; 14%-27%, and compression strength increased by 40%-76%; 38%-72% values to untreated wood.

• Proceedings of the KSCN Conference
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• 2005.10a
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• pp.86-86
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• 2005

• Journal of Korean Society of Forest Science
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• v.76 no.1
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• pp.27-32
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• 1987

Stomatal morphological characteristics (shape, density and length) were investigated for 8 ornamental woody species growing in the campus of Sangji College on Usandong, Wonju, Kangwondo. Stomata of Forsythia koreana, Syringa dialata, Zedkova serrata and Chaenomeles sinensis were classified as irregular-celled type (anomocytic), those of Vibrunum sargentii, Liriodendron tulipifera and Magnolia kobus as parallel-celled type (paracytic). For Forsythia koreana, stomatal length was not greatly changed as the leaf blade, growing larger. Number of stomata per unit leaf area was decreased, but number of stomata per single leaf was increased as the leaf blade, growing larger. For Taxus cuspidata, stomatal length was increased, but number of stomata per unit needle area was decreased as the needle, growing larger.

• The Korean Journal of Ecology
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• v.25 no.6
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• pp.399-403
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• 2002

Cellulose mass loss by cellulose filter papers was measured for 3 time (35 days, 70 days, 105 days) incubation during the growing season (from May to September 2002) with different tree density and after fertilization in a Japanese larch (Larix leptolepis) plantation. Cellulose mass loss rates were significantly different between tree density types and fertilization treatments during the study periods. After 105 day incubation of cellulose filter paper, cellulose mass loss rates were significantly higher in the low tree density (70.1 $\%$) than in the high tree density (49.9$\%$). Cellulose mass loss rates averaged 62.8$\%$ in the fertilization and 58.9% in the unfertilization treatments during the same periods. However, cellulose mass loss was not significantly different between the forest floor and the mineral soil layer except for 35 day incubation. The results indicate that cellulose decomposition rates are a useful index to express differences in organic matter decomposition activity in different tree density and after fertilizer treatments.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.49-55
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• 1978

In order to get healthy seedling of rice suitable for rice transplanter, the growing characteristics of the seedling grown under different growing days and sowing densities were invesigated and the results obtained were summarized as follows; In the 20 days old seedling, the difference of growing state of seed ling and its characteristics between the two types of nursery bed was not found, but for the 30 days old seedling, both of the crop growth rate and the relative growth rate on the band-type nursery bed appeared higher than those on the mat-type nursery bed. And also, "the dry weight, the content of cardohydrate and the ratio of dry weight to plant height of the seedling grown on the band-type nursery bed were much higher than those on the mat-type nursery bed, however the amount of difference of seedling characteristics between two types of nursery bed was decreased for 40 days old seedling and leaf number was not increased. The amount of the seedling growth was increased with less density of sowing and for the difference between the higher and the less density, the difference getting bigger with the longer nursery days. The maximum density of sowing was approximately 200cc per nursery case on the band-type nursery bed and 250cc per nursery case on the mat-type nursery bed. It was seemed that the growing uniformity of the seedling grown on the mat-type nursery bed was better than that on the band- type nursery bed, As the coefficient of variation of the plant height and the leaf numbers of the seedling grown on the band- type nursery bed was higher than that on the mat-type nursery bed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.133-140
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• 1978

Kernel softness. density. size and 100 kernel weight of Korean local corn lines (Zea mays, 1.) were studied to find any relationship with cultural magnitude in regions. Kernel density. softness and size were greater in the Kangwon area than in other less growing areas. Kernel size was the only character showing great relationship with growing magnitude. Most of the collected lines were flinty type and no differences were found among various growing magnitudes. Kernel density was also the same through the growing magnitudes.

• Korean Journal Plant Pathology
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• v.11 no.3
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• pp.252-257
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• 1995

Growth rates of the low temperature growing isolates, Pseudomonas fluorescens M45 and MC07, reached maximum stationary phase within 50 hrs at the low temperature, 4$^{\circ}C$. But an ordinary biocontrol agent P. putida Pf3 did not reach logarithmic growth phase until 80 hrs. The culture filtrates of M45 and MC07 significantly inhibited the mycelial growths of Pythium ultimum, Rhizoctonia solani and Phytophthora capsici. Detached cotyledons of cucumber grown on Murashige and Skoog agar medium were much enhanced in their growth, compared to those without the filtrates. Population densities of M45 and MC07 in the rhizosphere at 14$^{\circ}C$ were more stable than at 27$^{\circ}C$. When M45 and MC07 were treated into soil, the population density of MC07 continuously increased up to 9 days after treatment, and sustained the initial inoculum density up to 60 days. Cucumber damping-offs caused by P. ultimum and R. solani were significantly reduced by applying M45 as seed-inoculant and by soil treatment with MC07. The combined treatment of M45 and MC07 provided greater effect in reducing the disease incidence than that obtained by single treatments.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.78-82
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• 2010

This study investigated the effects of water-soluble calcium supplements manufactured with eggshells and oyster shells on growing rats. The aim was to review the potential use of food wastes as materials for water-soluble calcium supplements as compared to water-soluble calcium supplements made from imported seaweed powder. When experimental animals were administered three types of water-soluble calcium supplements orally for six weeks, the serum calcium level of the seaweed calcium supplement group were significantly higher than that of eggshell or oyster shell-derived calcium, but blood alkali phosphatase activity, osteocalcin and urine crosslink levels were not different in the three types of calcium supplements. Bone mineral density and bone mineral content in spine, femur and tibia also were not significantly different among the groups. However, when considering body weight of each group, bone mineral density and bone mineral content of the femur were significantly higher in the oyster shell calcium supplement group. These results suggest that at least on a short-term basis, the effect of calcium supplements prepared from eggshell and oyster shell are similar to the effects of seaweed calcium supplements.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.998-1007
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• 2021

Brine mineral water (BMW) is groundwater near the deep sea, and the mineral component of the BMW is different from the water of the deep sea because the components of BMW are derived from the unique geographical features surrounding it. Recently, BMW has attracted attention due to the unique health-related minerals it possesses; however, the influence of BMW on physiological function has not yet been determined in domestic animals. Therefore, this experiment investigated the influence of BMW on the growth performance, water intake, blood properties, and immunoglobulin (Ig) levels of serum in growing-finishing pigs. A total of 64 pig barrows (Landrace × Yorkshire × Duroc) with an average initial weight of 40.56 ± 0.17 kg were used in the experiment, and 0%, 2%, 3%, and 5% samples of BMW diluted with freshwater were provided to experimental animals during the 56 days. We found that the gain/feed ratio in the 3% BMW group was significantly higher than that in the 5% BMW group of growing-finishing pigs (p < 0.05). The water intake was significantly increased in the 5% BMW group compared with the other groups (p < 0.05) of growing-finishing pigs. Additionally, the concentrations of red blood cells (RBCs), hemoglobin (HGB), and hematocrit (HCT) were significantly higher in the 3% BMW group than in the control group. The level of high-density lipoprotein cholesterol was higher in the 3% BMW group than in the 5% BMW group (p < 0.05). Furthermore, IgG and IgM levels in the serum were significantly higher in the 2% and 3% BMW groups than in the control group (p < 0.05). These results suggest that a dilution of 3% BMW in the intake water could improve the levels of RBCs and serum Igs in growing-finishing pigs.