• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.273-291
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• 2020

The strength characteristics of the three orthogonal splitting planes, known as rift, grain and hardway planes in granite quarries, were examined. R, G and H specimens were obtained from the block samples of Jurassic granites in Geochang and Hapcheon areas. The directions of the long axes of these three specimens are perpendicular to each of the three planes. First, The chart, showing the scaling characteristics of three graphs related to the uniaxial compressive strengths of R, G and H specimens, were made. The graphs for the three specimens, along with the increase of strength, are arranged in the order of H < G < R. The angles of inclination of the graphs for the three specimens, suggesting the degree of uniformity of the texture within the specimen, were compared. The above angles for H specimens(θ^H, 24.0°~37.3°) are the lowest among the three specimens. Second, the scaling characteristics related to the three graphs of RG, GH and RH specimens, representing a combination of the mean compressive strengths of the two specimens, were derived. These three graphs, taking the various N-shaped forms, are arranged in the order of GH < RH < RG. Third, the correlation chart between the strength difference(Δσ_t) and the angle of inclination(θ) was made. The above two parameters show the correlation of the exponential function with an exponent(λ) of -0.003. In both granites, the angle of inclination(θ^RH) of the RH-graph is the lowest. Fourth, the six types of charts, showing the correlations among the three kinds of compressive strengths for the three specimens and the five parameters for the two sets of microcracks aligned parallel to the compressive load applied to each specimen, were made. From these charts for Geochang and Hapcheon granites, the mean value(0.877) of the correlation coefficients(R²) for total density(Lt), along with the frequency(N, 0.872) and density(ρ, 0.874), is the highest. In addition, the mean values(0.829) of correlation coefficients associated with the mean compressive strengths are more higher than the minimum(0.768) and maximum(0.804) compression strengths of three specimens. Fifth, the distributional characteristics of the Brazilian tensile strengths measured in directions parallel to the above two sets of microcracks in the three specimens from Geochang granite were derived. From the related chart, the three graphs for these tensile strengths corresponding to the R, G and H specimens show an order of H(R1+G1) < G(R2+H1) < R(R1+G1). The order of arrangement of the three graphs for the tensile strengths and that for the compressive strengths are mutually consistent. Therefore, the compressive strengths of the three specimens are proportional to the three types of tensile strengths. Sixth, the values of correlation coefficients, among the three tensile strengths corresponding to each cumulative number(N=1~10) from the above three graphs and the five parameters corresponding to each graph, were derived. The mean values of correlation coefficients for each parameter from the 10 correlation charts increase in the order of density(0.763) < total length(0.817) < frequency(0.839) < mean length(Lm, 0.901) ≤ median length(Lmed, 0.903). Seventh, the correlation charts among the compressive strengths and tensile strengths for the three specimens were made. The above correlation charts were divided into nine types based on the three kinds of compressive strengths and the five groups(A~E) of tensile strengths. From the related charts, as the tensile strength increases with the mean and maximum compressive strengths excluding the minimum compressive strength, the value of correlation coefficient increases rapidly.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.58-72
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• 2006

In recent years, not only the occurrences but the magnitude of earthquakes in Korea are on an increasing trend and other sources of dynamic events including large-scale construction, operation of hi띤-speed railway and explosives blasting have been increasing. Besides, the probability of exposure fir rock joints to free faces gets higher as the scale of rock mass structures becomes larger. For that reason, the frictional behavior of rock joints under dynamic conditions needs to be investigated. In this study, a shaking table test system was set up and a series of dynamic test was carried out to examine the dynamic frictional behavior of rock joints. In addition, a computer program was developed, which calculated the acceleration and deformation of the sliding block theoretically based on Newmark sliding block procedure. The static friction angle was back-calculated by measuring yield acceleration at the onset of slide. The dynamic friction angle was estimated by closely approximating the experimental results to the program-simulated responses. As a result of dynamic testing, the static friction angle at the onset of slide as well as the dynamic friction angle during sliding were estimated to be significantly lower than tilt angle. The difference between the tilt angle and the static friction angle was $4.5\~8.2^{\circ}$ and the difference between the tilt angle and the dynamic friction angle was $2.0\~7.5^{\circ}$. The decreasing trend was influenced by the magnitude of the base acceleration and inclination angle. A DEM program was used to simulate the shaking table test and the result well simulated the experimental behavior. Friction angles obtained by shaking table test were significantly lower than basic friction angle by direct shear test.

• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.166-178
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• 2006

Recently, the frequency of occurring dynamic events such as earthquakes, explosives blasting and other types of vibration has been increasing. Besides, the chances of exposure for rock discontinuities to free faces get higher as the scale of rock mass structures become larger. For that reason, the frictional behavior of rock joints under dynamic conditions needs to be investigated. In this study, artificially fractured rock joint specimens were prepared in order to examine the dynamic frictional behavior of rough rock joint. Roughness of each specimen was characterized by measuring surface topography using a laser profilometer and a series of shaking table tests was carried out. For mated joints, the static friction angle back-calculated ken the yield acceleration was $2.7^{\circ}$ lower than the tilt angle on average. The averaged dynamic friction angle for unmated joints was $1.8^{\circ}$ lower than the tilt angle. Displacement patterns of sliding block were classified into 4 types and proved to be related to the first order asperity of rock joint. The tilt angle and the static friction angle for mated joints seem to be correlated to micro average inclination angle which represents the second order asperity. The tilt angle and the dynamic friction angle for unmated Joints, however, have no correlation with roughness parameters. Friction angles obtained by shaking table test were lower than those by direct shear test.

• Archives of Plastic Surgery
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• v.35 no.1
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• pp.48-55
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• 2008

Purpose: We measured linear distances, angles and inclinations on the cast models of the noses, and compared these indirect measurements with the direct measurements obtained from the nose in order to validate the accuracy of the indirect anthropometry using the cast model. Methods: Subjects were 50 males and 50 females, medical students in twenties(mean 27.1 years). Cast models were made from the alginate impression material and the plaster. In direct anthropometry, 16 linear, 7 angular, and 2 inclination measurements between 11 landmarks on the nose were obtained using sliding caliper, spreading caliper, and fabric tape measure. At the same time, the same measurements were obtained from the cast models of the same people. Total 25 measurements were compared, and tested by the independent t-test of SPSS. Results: The standard values of Korean nose in twenties were obtained. 24 measurements except the columellar labial angle were not statistically different between the indirect anthropometry and the direct anthropometry. Conclusion: Indirect anthropometry on the cast model of the nose revealed no significant difference from the anthropometric measurement statistically, accounting for 24 in 25 measurements(96%). There are two possible reasons that caused the difference of columellar labial angle between direct and indirect anthropometry. First, the columellar labial angle could be decreased by protrusion of the lips which resulted from contracting mouth in which an drinking straw had been applied on the mouth corner for patients' respiration during making cast model. Second, it is generally known that the columellar labial angle could be measured larger when soft tissues were pressed by protractor in direct anthropometry. Using a drinking straw with greater diameter, and scheming respiration through the nostrils that patients don't feel discomfort, the more accurate data would be obtained from the indirect anthropometry using the cast models of the noses.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.439-446
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• 2009

This is a study intended to investigate the environmental factors including vegetation and soil in order to better understand the environmental and ecological characteristics of four different habitats of Pulsatilla tongkangensis(Mt. Baekun, Maha-ri, Kyulam-ri and Mt. Deokhang). These habitats, according to investigations, are mostly located on the slopes of mountains facing northwest at an altitude of 220m to 772m above sea level with angles of inclination ranging from 41 degree to 85 degree. A total of 27 vascular plant taxa are identified in ten quadrates of the four habitats. The importance value of these plants is as follows: Pulsatilla tongkangensis is 9.65%; Carex humilis var. nana 28.93%; Potentilla dickinsii 16.55%; Mukdenia rossii 7.09%; Peucedanum terebinthaceum and Eragrostis ferruginea 4.55%; and Vicia venosa var. albiflora 3.90%. The importance value of these six species is high, so they are at affinity with P. tongkangensis m their habitats. The degree of their average species diversity is 0.75, and that of dominance and evenness 0.24 and 0.85, respectively. Their average field capacity of soil is 19.05%, organic matter 10.51%, and soil pH is 7.43, which are similar among their habitats.

• Korean Journal of Plant Taxonomy
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• v.40 no.3
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• pp.135-144
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• 2010

This study intended to investigate environmental factors including soil and vegetation in order to understand the environmental and ecological characteristics of four different habitats of Abelia tyaihyoni. These habitats, according to investigations, are mostly located at elevations of 203 m to 297 m with angles of inclination ranging from 9 degrees to 17 degrees. The litter depth of habitats is 2 cm to 5 cm. A total of 113 vascular plant taxa are identified in seven quadrates of the four habitats. The life form of 113 species is H-$D_4$-$R_5$-e type. The importance value of Abelia tyaihyoni is 39.61%, and 4 highly ranked species such as Quercus dentata (6.27%), Spiraea blumei, Spiraea prunifolia for. simpliciflora (4.04%) and Ulmus davidiana var. japonica (3.84%) are considered to be an affinity with Abelia tyaihyoni in their habitats. The dominant species of woody plants in the four habitats are represented as Pinus densiflora (21.22%) and Quercus dentata (16.82%) in the subtree layer (T2), and Carex humilis var. nana (18.95%) and Carex lanceolata (17.63%) in the herbaceous layer (H). The degree of their average species diversity is 1.42, and that of dominance and evenness are 0.07 and 0.86, respectively. The type of soil is sandy loam, clay loam and loam, and the average field capacity of soil is 22.49%. Their average organic matter is 9.39%, soil pH 6.75, and available phosphorus is $1.23 {\mu}g/g$.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.64-78
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• 2015

The environmental characteristics of Astilboides tabularis were investigated to compile basic data for conservation and restoration. Natural habitats, according to investigations, were mostly located on the slopes of mountains facing north at an altitude of 432 m to 1,413 m above sea level with angles of inclination ranging from 16 degree to 49.5 degree. A total of 246 vascular plant taxa were identified from 12 quadrats in 11 habitats. The importance value of Astilboides tabularis is 20.40%, and 6 highly ranked species such as Dryopteris crassirhizoma (4.56%), Rodgersia podophylla (3.72%), Astilbe rubra (2.81%), Carex siderosticta (2.67%), Ainsliaea acerifolia (2.65%), and Meehania urticifolia (2.46%) are considered to be an affinity with Astilboides tabularis in their habitats. Average species diversity was 1.23, dominance and evenness were found to be 0.11 and 0.86, respectively. The litter depth above the soil surface was 2 to 10 cm, and soil depth was 20.8 to 67.5 cm. The soil texture of habitats were divided three types such as loam, silt loam, and sandy loam. The soil pH was 5.63 to 7.74, and the organic matter and nitrogen contents were ranged from 8.88 to 42.55%, and 1.40 to 6.58 mg/g, respectively.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.497-506
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• 2010

This study intended to investigate the environmental factors including soil and vegetation in order to better understand the environmental and ecological characteristics of ten different habitats of $Hanabusaya$ $asiatica$. These habitats, according to investigations, are mostly located on the slopes of mountains facing north at an altitude of 580 m to 1,396 m above sea level with angles of inclination ranging from 5 degrees to 80 degrees. A total of 146 vascular plant taxa are identified in 32 quadrates of the ten habitats. The importance value of $H.$ $asiatica$ is 8.87%, and 5 highly ranked species such as $Carex$ $siderosticta$ (8.67%), $Ainsliaea$ $acerifolia$ var. $subapoda$ (7.10%), $Calamagrostis$ $arundinacea$ (6.79%), $Athyrium$ $yokoscense$ (5.33%), $Astilbe$ $rubra$ (3.11%) are considered to be an affinity with $H.$ $asiatica$ in their habitats. Dominant species of woody plants in ten habitats are represented as $Quercus$ $mongolica$ in tree layer (T1), $Acer$ $pseudo$-$sieboldianum$ in subtree layer (T2), $Rhododendron$ $schlippenbachii$ and $Tripterygium$ $regelii$ in shrub layer (S). The degree of their average species diversity is 1.30, and that of dominance and evenness are 0.08 and 0.88, respectively. The type of soil is sandy loam, loam and loamy sand, and the average field capacity of soil is 23.95%. Their average organic matter is 12.28%, soil pH 5.79, and available phosphorus is 25.48%. Correlation coefficients analysis based on environmental factors, vegetation and soil analysis shows that the coverage of tree layers is correlated with richness, diversity, dominance, evenness and coverage of $H.$ $asiatica$.

• Korean Journal of Plant Resources
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• v.27 no.2
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• pp.155-173
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• 2014

The habitats characteristics of Exochorda serratifolia were investigated to compile basic data for conservation and restoration. Natural habitats were located at an altitude of 1 m to 624 m above sea level with angles of inclination ranging from 2 degrees to 81 degrees. A total of 248 vascular plant taxa were identified from 37 quadrats in 16 habitats. The importance value of Exochorda serratifolia is 18.70%, and 5 highly ranked species such as Rhododendron mucronulatum (3.79%), Abelia tyaihyoni (3.27%), Euonymus alatus for. ciliatodentatus, Quercus mongolica (3.23%), and Indigofera kirilowii (2.97%) are considered to be an affinity with Exochorda serratifolia in their habitats. Species diversity was 1.03, dominance and evenness were found to be 0.15 and 0.85, respectively. Average field capacity was 24.19%, the organic matter was 8.21%, pH was 5.52, and available phosphorus was $7.71{\mu}g/g$. Correlation coefficients analysis based on environmental factors, vegetation, and soil analysis shows that the coverage of Exochorda serratifolia is correlated with field capacity and available phosphorus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.43-51
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• 2020

This study examined how the eight-week spinal stabilization exercise program affects the cervical disability index, postural balance ability, and body shape change. The exercise program performed 60 minutes of spinal stabilization exercise three times a week for eight weeks. Sixteen patients with chronic neck pain, who complained of neck pain for six months, were classified into exercise group (n=8 patients) and control group (n=8 patients). The results before and after the eight-week exercise program were observed. Significant differences were observed in the time, group, and interaction of the neck disability index (p<.05). The balance ability showed significant interaction effects between the groups and periods (p<.05). Significant differences were noted in the timing and interaction in the pelvic inclination angle in posture change (p<.05), and there were significant differences in the group, timing, group, and interaction in the cervical and shoulder position angles (p<.05). The above results showed that the spinal stabilization exercise significantly improved the cervical disability index, balance ability change, and body shape change in patients with chronic neck pain. Future studies will analyze the specific changes in spinal structure through radiographic imaging to increase the validity of spinal stabilization exercise.