• Journal of the Korean Ceramic Society
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• v.34 no.11
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• pp.1139-1150
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• 1997

A model for predicting the relative density and the compressive strength of open-cell ceramics with three-dimensional network structure was proposed through the interpretation of their macrostructure and fracture mechanics. The equation predicting the relative density was derived under the assumption that the open-cell structure was a periodic array of the tetrakaidecahedron unit cell consisting of cylindrical struts containing the internal hollow with the shape of a triangular prism. The model for compressive strength of open-cell ceramics with the hollow strut was also developed by modifying conventional model which based on fracture behavior of them subjected to the compressive stress. Both the relative density and the compressive strength were expressed in terms of the ratio of the strut diameter to the length together with the ratio of the hollow size to the strut diameter. The proposed model for the relative density and the compressive strength of the alumina-zirconia composite with open-cell structure were accorded well with the experimental values, whereas Gibson-Ashby and Zhang's model did not show such a good agreement.

• Journal of Oral Medicine and Pain
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• v.45 no.4
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• pp.83-88
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• 2020

Purpose: Growth differentiation factor 11 (GDF11) and myostatin (MSTN) are closely-related transforming growth factor β family members reported to play crucial roles in bone formation. We previously reported that, in contrast to MSTN, GDF11 promotes osteogenesis of vertebrae and limbs. GDF11 has been also reported as an important regulator in tooth development by inducing differentiation of pulp stem cells into odontoblasts for reparative dentin formation. The goal of this study was to investigate the differential roles of GDF11 and MSTN in dental and cranial bone formation. Methods: Micro-computed tomography analysis was performed on cranial bones, including frontal, parietal, and interparietal bones, and lower incisors of wild-type, Gdf11 knockout (Gdf11-/-), and Mstn knockout (Mstn-/-) mice. Tissue volume, thickness, and mineral density were evaluated for both cranial bone and lower incisors. Lower incisor lengths were also measured. Because Gdf11-/- mice die shortly after birth, analysis was performed on newborn (P0) mice. Results: Compared to those of Mstn-/- mice, cranial bone volume, thickness, and mineral density levels were all significantly diminished in Gdf11-/- mice. Tissue mineral density of Gdf11-/- mice were also significantly decreased compared to wild-type mice. Likewise, lower incisor length, tissue volume, thickness, and mineral density levels were all significantly reduced in Gdf11-/- mice compared to Mstn-/- mice. Incisor length was also significantly decreased in Gdf11-/- mice compared to wild-type mice. Mstn-/- mice exhibited mildly increased levels of tissue volume, thickness, and density in cranial bone and lower incisor compared to wild-type mice although statistically not significant. Conclusions: Our findings suggest that GDF11, unlike MSTN, endogenously promotes cranial bone and tooth development.

• Journal of Ginseng Research
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• v.19 no.3
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• pp.287-290
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• 1995

This study was conducted to elucidate the effect of physical properties of soil in nursery bed with different densities on growth of ginseng seedling. Stem length, leaf length and leaf width of ginseng seedling showed the decreasing tendency with increasing the hardness of the nursery soil. Fresh root weight per seedling and number of available seedlings were increased significantly with decrease of the soil hardness. For solid, liquid phases, bulk density and hardness of soil, negative correlations were shown in stem length, leaf length, leaf width, root weight per seeding, and number t of available seedlings. On the other hand, gas phase, air permeability and porosity of soil had positive correlations with stem length, leaf length, leaf width, root weight per seedling and number of available seedlings. Key words Yang-Jik nursery, ginseng seedling, soil physical properties.

• Journal of the Korean Statistical Society
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• v.27 no.1
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• pp.91-100
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• 1998

A method of estimating probability density using regression tools is presented here. It is based on equal-length binning and locally weighted approximate likelihood for bin counts. The method is particularly useful for densities with bounded supports, where it automatically corrects edge effects without using boundary kernels.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.219-225
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• 2004

This study was conducted to evaluate growth and yield characteristics and the contribution to the yield according to the emergent sequence of tiller under two planting density $(60{\times}15\;cm,\;60{\times}25\;cm)$ in Coix lachryma-jobi L. var. mayuen Stapf. The average culm length and number of rachillas of $60{\times}25\;cm$ planting density were 20 cm shorter and 4.7 higher, respectively, whereas seed setting position of $60{\times}25\;cm$ planting density was 1.7 nodes lower compared with $60{\times}15\;cm$ planting density. Culm length and culm diameter of each tiller became shorter and thinner as the tiller emerged later. Length of rachillas was longer, number of grains was higher and ripening rate was also higher in $60{\times}25\;cm$ planting density than those of $60{\times}15\;cm$ planting density, whereas 100 grain weight in $60{\times}25\;cm$ planting density was lower by 0.5 g compared with $60{\times}15\;cm$ planting density. Length of rachillas and number of grains according to the emergent sequence of tiller were shown shorter and lower as the tiller emerged later. The highest number of bract was obtained from the main culm in both planting densities. 100 grain weight according to the emergent sequence of tiller became lower as the tiller emerged later in $60{\times}15\;cm$ planting density, but there was no clear tendency in $60{\times}25\;cm$ planting density. Among 8 tillers, 5th tiller and 4th tiller of main culm contributed 84.4% to the yield in $60{\times}15\;cm$ planting density, while it was 84.1% in $60{\times}25\;cm$ planting density. Analysis of path coefficient to grain yield showed that direct effect was the highest in the number of grain per tiller followed by in the 100 grain weight and in ripening rate.

• Progress in Superconductivity
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• v.2 no.1
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• pp.11-14
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• 2000

The notion of the finite pairing interaction energy range Td is shown to result in a linear temperature dependence of the London magnetic penetration depth length, ${\Delta}{\lambda}{/\lambda}(0)=(T/Td)2/\pi)ln2$ at low T in the case of the s-wave pairing state, accounting for data of high Tc superconductor by Hardy et al.

• Applied Microscopy
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• v.19 no.2
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• pp.85-98
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• 1989

The ventricular myocardia of 14, 16, 18 and 20-day-old rat fetuses and newborns have been studies by light and electron microscopic morphometrics. The volume density of the myocyte and interstitial compartments as well as volume, surface and numerical density of nuclei were estimated by light microscopic morphometrics. Whereas, the volume density of myofibrils and glycogen granules as well as the volume, surface and numerical density of mitochondria were assessed by electron microscopic morphometrics. The volume density of myocyte compartment of the ventricular myocardia in developing fetuses decreased, but increased in newborn rats. On the other hand, the volume density of the interstitial compartment increased in growing fetuses and decreased in newborns. In all groups the volume, surface and numerical density of nuclei decreased gradually with elongation of myocytes. Conversely, the volume, surface and numerical density of mitochondria and volume density of myofibrils and glycogen granules in ventricular myocytes incresed. The increase in numerical density of mitochondria probably reflects an increase in metabolic activity. Sarcomere length also increased during development.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.62-66
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• 1984

One row of pollen parent to two rows of seed parent (1:2), 2:4 and solid (1:2) planting patterns (PP) were compared in seed parent densities of 3,500, 5,000 and 6,500 plants per 10 ares to determine effects of PP and plant density on growths of seed and pollen plants, and seed yield of seed parent of modified single cross corn hybrid. Planting pattern did not significantly affect agronomic characteristics of seed plant except ear number per 100 plants and seed yield which were greater in solid and 1:2 PP than in 2:4 PP. Significant PP x plant density interaction did not exist for agronomic characteristics of seed parent. In the seed parent, plant height and 100 kernel weight were not affected by plant density, but ear height, ear number per 100 plants, and kernel number per ear were linearly decreased with increased plant densities. Seed yield ranged from 330 to 460 kg per 10 ares and overall yield response to plant density was quadratic. Tassel length and spikelet number per tassel of the pollen parent were significantly affected by PP and plant density. Significant PP x plant density interaction existed for tassel length and spikelet number per tassel. Tassel length and spikelet number per tassel were greater in 1:2 and 2:4 PP compared to solid PP and were greatly reduced with increased plant densities in solid and 1:2 PP. The results indicated that 1:2 or 2:4 PP at around 5,000 plants per 10 ares for seed parent would be suitable for seed production of modified single cross com hybrid.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.215-222
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• 1996

This study was conducted to compare the growth and yield, and to determine the optimum planting date and density in two improved black soybean varieties. The two varieties were planted by driller attached a tractor on May 21 and June 19, 1993, and treated five planting densities, respectively. Yield of Gumjeongkong 1 was similer for both planting dates, but that of Suwon 157 was remarkably reduced on June 19 planting compared to May 21. There was significant differences between planting dates in stem length, number of branches, seeds per plant, seed weight and yield. Planting density, also, significantly affected on stem length, number of branches and seeds per plant. Statistically significant interactions between planting date$\times$variety and planting date$\times$planting density were found at almost all characteristics, except between variety$\times$planting density. Optimum planting date and density of Gumjeongkong 1 for high yield were June 19 and 33, 000 plants per l0a, and those of Suwon 157 were May 21 and 22, 000 plants per l0a, respectively. The coefficient of variation at different planting densities was high at stem length, number of branches, seeds per plant and yield, but low at number of main stem node, seeds per pod and 100 seed weight.

• Korean Journal of Medicinal Crop Science
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• v.12 no.4
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• pp.300-303
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• 2004

This experiment was conducted to study the effect of growth characteristics and yield by different planting density on Wasabia japonica Matsum. in water culture. Plant height, leaf length, petiole length was long in spacious planting $(30{\times}25\;cm)$ and short in dense planting$(30{\times}15\;cm)$. Rhizome width was thick in spacious planting, and was thin in dense planting. Rhizome weight per plant decreased by increasing planting density, but rhizome yield was increased by high planting density. But distribution of rhizome weight did not show significant difference at different planting density.