• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.5
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• pp.47-56
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• 2023

The Quercus variabilis and Quercus dentata, which are said to be relatively drought tolerant among the important genus Quercus that represent deciduous broad-leaved forests in Korea. These two species are widely distributed worldwide in Korea, Japan and China (northern, central, western and eastern subtropical regions). This study compared the ecological niche breadth and overlap according to growth response in 4 soil moisture gradients for the two species and tried to reveal degree of competition and ecological niche characteristics. The ecological niche breadth was 0.977±0.020 for Q. variabilis and 0.979±0.014 for Q. dentata, the latter being slightly wider. And they were similar in 5 traits (stem length, leaf lamina length, leaf width length, stem weight, leaf petiole weight), Q. variabilis was more dominant in 4 traits (leaves number, stem diameter, leaf area, leaf petiole length), and Q. dentata was more dominant in 7 traits (root length, shoot length, plant weight, root weight, shoot weight, leaf weight, leaf petiole weight). The ecological niche overlap for soil moisture between the two species overlapped most in plant structure-related traits and least in photosynthetic organ-related traits such as petiole length. As a result of principal component analysis, degree of competition between the two species for soil moisture was more severe when the soil moisture condition was low than high. Among the measured traits that affect the two-dimensional distribution, 8 traits (Leaves number, Shoot length, Stem length, Plant weight, Root weight, Shoot weight, Stem weight, Leaves weight) were correlated with the factor 1, and 2 traits (Leaf width length, Leaf petiole weight) were correlated with the factor 2 (r>0.5). These results show that the ecological response of the two species to soil moisture is not a few traits involved, but several traits are involved simultaneously.

• Journal of Periodontal and Implant Science
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• v.53 no.6
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• pp.467-477
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• 2023

Purpose: The purpose of this study was to evaluate the regenerative capacity of stem cells combined with bone graft material and a collagen matrix in rabbit calvarial defect models according to the type and form of the scaffolds, which included type I collagen matrix and synthetic bone. Methods: Mesenchymal stem cells (MSCs) were obtained from the periosteum of participants. Four symmetrical 6-mm-diameter circular defects were made in New Zealand white rabbits using a trephine drill. The defects were grafted with (1) group 1: synthetic bone (β-tricalcium phosphate/hydroxyapatite [β-TCP/HA]) and 1×10⁵ MSCs; (2) group 2: collagen matrix and 1×10⁵ MSCs; (3) group 3: β-TCP/HA, collagen matrix covering β-TCP/HA, and 1×10⁵ MSCs; or (4) group 4: β-TCP/HA, chipped collagen matrix mixed with β-TCP/HA, and 1×10⁵ MSCs. Cellular viability and cell migration rates were analyzed. Results: Uneventful healing was achieved in all areas where the defects were made at 4 weeks, and no signs of infection were identified during the healing period or at the time of retrieval. New bone formation was more evident in groups 3 and 4 than in the other groups. A densitometric analysis of the calvarium at 8 weeks post-surgery showed the highest values in group 3. Conclusions: This study showed that the highest regeneration was found when the stem cells were applied to synthetic bone along with a collagen matrix.

• Journal of Korean Society of Forest Science
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• v.5 no.1
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• pp.27-32
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• 1966

Taking an opportunity of the application of clearcutting method, 140 red pine (Pinus densiflora Sieb. et Zucc.) trees grown at Chon-nam province, the southern part of South Korea, were fellen and the tree height, clear-bole length, D.B.H. diameter at base(0.2m above from the ground line) and the length of the longest branch were measured. The correlation between factors mentioned were analysed. The results are summarized as follows: 1. The correlation between crown length and tree height (r=0.821) was sinificant. 2. The correlation between the diameter at base and D.B.H. was highly significant (r=0.961). D.B.H. can be calculated from multiplying the diameter at base by 0.88. 3. A weak relation between D.B.H and tree height was abserved. 4. The positive correlation between tree height and clear-bole-length was calculated, but it was not sharp between D.B.H. and the length of the longest branch. 5. The height, basal area, D.B.H. and volume increment by tree class calculated from the data of the stem analysis are presented (Tab. 3~10).

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.633-642
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• 2023

Purpose: The variation of the internal diameters of gun barrel incurs a lot of reworks in gun barrel manufacturing process and the significant quality problem of gun barrel. And it is likely to stem from the current measurement system for the internal diameter of gun barrel and the related manufacturing process as well. The purpose of this study is to improve the gun barrel manufacturing process through improving measurement system. Methods: The improved measurement system using laser can measure the internal diameters of gun barrel more accurately, and the properly adjusted honing process reduces the variation of internal diameters of gun barrel. Results: Comparing the mean square error of internal diameters for 6 gun barrels measured before and after process improvement shows that the variation of gun barrel internal diameters was significantly reduced after the process improvement. Conclusion: The introduction of improved measurement system for the internal diameters of gun barrel and the adjustment of related honing process results in the reduction of reworks of gun barrels and their internal diameter variations.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.269-281
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• 2016

The statistical analyses of coefficient of variation, heritability, and genetic advance were carried out to identify differences in morphological characteristics, such as the stem and inflorescence length, of 10 major commercial cultivars of spray chrysanthemum (Chrysanthemum morifolium). For morphological characteristics, stem lengths ranged from 46.4 cm to 54.9 cm, the maximum diameter of stem was 5.6 to 8.5 mm, the hardness of the stem was 0.17 to $0.70kg{\cdot}m^{-2}$, the fresh weight of stem was 7.5 to 17.5 g, the dry weight of the stem was 1.6 to 3.3 g, the ratio of dry weight/fresh weight of stem was 15.9% to 23.1%. Also, the number of leaves on the stem was 8.4 to 12.2, the stem leaf area was 17.8 to $37.8m^2$, the fresh weight stem leaves was 5.3 to 18.6 g, the dry weight was 0.5 to 1.4 g and the ratio of dry weight /fresh weight of stem leaves was 7.6% to 11.5%. The inflorescence length ranged from 10.1 to 18.6 cm, the fresh weight of inflorescence was 7.3 to 26.7 g, the dry weight of inflorescence was 1.2 to 2.8 g, the ratio of dry weight /fresh weight of inflorescence was 10.4% to 17.1%. For flower, the diameter of the flower center was 8.2 to 13.3 mm, the petal width was 5.7 to 14.0 mm, the petal length was 12.9 to 33.1 mm, and the petal thickness was 157.8 to $354.4{\mu}m$. The mean values of each character in each cultivar were very different, and DMRT and LSD values based on morphological characteristics among 10 cultivars were highly significant. For variability and genetic parameters, the lowest CV (coefficient of variation), PCV (phenotypic coefficient of variation), and GCV (genotypic coefficient of variation) were 4.79% to 5.15% in stem length, and the highest variations were 62.97% to 65.21% in leaf area. ECV (error or environmental coefficient of variation) was the lowest for leaf area (1.71%) and it was the highest for leaf dry weight (19.30%). Heritability also significantly differed among the characteristics, ranging from 68.69% to 99.67%, the lowest value was shown in ratio of dry weight /fresh weight of stem and the highest value was for leaf area of stem. The value for genetic advance was the lowest in hardness of stem at 0.30 and the highest in leaf thickness at 156.65. The lowest genetic advance as percentage of mean of stem hardness was 9.17%, while the highest percentage of stem length was 134.27%. Thus the characters which had the highest values indicated above show the influence of additive gene action and may provide useful resources for selection programs for agronomic improvement.

• Korean Journal of Plant Resources
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• v.6 no.2
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• pp.147-154
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• 1993

The experiment was carried out to study the influence of seeding dates, planting densities and fertilizer application levels on some agronmic characters and yield of fresh weight in Agastache rugosa. The results obtained are summarized as follow; Fresh weight was increased on Apr. 1 seeding date. Therefore, optimum time for sowing was on Apr. 1. Stem length was long in dense planting and short in spacious planting. Stem diameter was thick in spacious planting, and was thin in dense planting. Yield was higher in dense planting densities($10{\times}20cm:50\;plants/m^2,\;20{\times}20cm:25\;plants/m^2,\;(30{\times}20cm:17\;plants/m^2$) Fertilizing ($N:P_2O_5;K_2O=6:6:6kg/10a$) was increased than without fertilizing because stem length and number of leaf were good.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.2
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• pp.143-146
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• 1991

The present experiment was carried out to investigate the effects of direct sowing time culture of Perilla frutescens var. acuta KUPO on growth yield and it's components. The number of days from seeding to emergence was recognized linear negative correlation between seeding dates. Stem length was the longest in Apr. 1 seeding, and was short in the early, and the late seeding. Stem diameter was the thickest in Apr. 1 seeding, and was thin in the early, and the late seeding. Dry weight of leaf and stem was increased on Apr. 1 seeding. Grain yield was the highest in Apr. 1 seeding date. Therefore, optimum time for direct sowing was on Apr. 1.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.2
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• pp.111-118
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• 2006

It is indispensable to grasp the turning ability of a ship to operate her effectively. For this purpose, the author measured the turning ability of training ship, A-RA by use of bow thruster and stem rudder. The turning ability of this ship, in case of using both of stem rudder and bow thruster at the same time, caused by increase of steering angle provides more influence to the size of tactical diameter than it caused by the power of bow thruster. But the influence of bow thruster on the turning ability is available only within rudder angle $5^{\circ}\;-\;10^{\circ}$, so it is possible to grasp that the effect of bow truster is reduced as rudder angle become bigger. In case of the influence of bow thruster by her speed, the ability of bow thruster is very effective at low speed, but it is almost not available in normal turning speed. Therefore, the using both of stem rudder and bow thruster can be useful in case of low speed proceeding at entrance or departure of the narrow waterway or inside port which sea traffic is congest for collision avoidance.

• Journal of Bio-Environment Control
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• v.13 no.2
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• pp.120-123
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• 2004

This study was conducted to investigate the effect of brushing on overgrowth inhibition, growth, yield and starch content in spring-grown potato in the netted house. The plant growth of aerial parts was inhibited with growth stage and brushing duration. Especially, The number of lateral branches decreased greatly with brushing duration. The stem length and stem diameter were not different significantly between brushing and non-brushing on May 6. But the stem length was long in later growth stage but short in longer brushing duration. Chlorophyll content by SPAD increased with growth stage regardless of non-brushing duration and ranged from 30 to 36 mg/$\textrm{cm}^2$. The fresh and dry weight of aerial part and tuber were heavy in longer brushing duration. Starch content was higher in brushing treatment as compared to non-brushing and increased with brushing duration.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.3
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• pp.190-194
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• 1993

This experiment was conducted to investigate the effects of concentrated sulfate on the germination rate, growth rate and the productivity of weight of kudzu (Pueraria thwnbergiana Bentham). The germination rate of kudzu seed by one or two treatment retreatment with the concentrated sulfate for minutes of 5. 10, 15 and 20 were determined respectively. The results obtained were summarized as follows; 1. In the time of concentrated sulfate treatment, the germination rate was the highest in the once treatment for 20 minute. and the retreatment was higher than the once treatment in the germination rate. 2. The changes of plant length by growth stage was grown gradually until for 60 day and rapidly after for 60 day. The growth rate was the highest in treatment for 15 minute than in other treatments. 3. The stem diameter. stem weight. fresh weight and root weight by the treatment with sulfate 15 minute as the treatment with once were high degree of productivity. 4. The number of branch. number of nodes and root weight by the growth stage were higher growth rate before for 90 day than after for 90 day, however stem weight and fresh weight were high degree of productivity after for 60 day.