• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.133-138
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• 1997

The technology of removing phosphorous, considered as one of the most important control nutrients causing eutrophication in various water bodies, have been investigated by many researchers. Recently, phosphorous crystallization process is emerging as a new technology for phosphorous removal. In this study, waste oyster shells which can be easily obtained from the ocean, were used as a seed crystal, and their effects of several physical/chemical factors on the phosphorous removal efficiencies were examined by batch tests. Ca$^{2+}$ and pH affected phosphorous crystallization process using waste oyster shells. As alkalinity of wastewater increased, phosphorous removal efficiencies gradually decreased. Phosphorous removal efficiencies were increased, as specific area and contact efficiency per unit area of waste oyster shells were increased. In case of high temperature, phosphorous crystallization process was rapidly advanced and phosphorous removal efficiencies were increased. Dependig on X-ray diffraction analysis, it was showed that generation materials extracted from the surface of waste oyster shells with short reaction time were dominated by $CaHPO_4\cdot 2H_2O$, but progressed to $Ca_5(OH)(PO_4)_3$. The SEM observation reveals that the evident variations were hardly seen, but particle sizes of waste oyster shells were relatively bigger and showed forms of smaller plate than before.

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.190-201
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• 2022

Background: The introduction of new living modified (LM) crops may pose a latent threat to the biodiversity of each country. Here, we used sunflowers (Helianthus annuus L.) as a study system to investigate the potential for invasiveness of LM crops under different environmental conditions when released into a natural ecosystem in South Korea. We examined the seed germination, survival, and flowering of sunflowers under competition with wild plants at different sowing dates (March-December) and plot sizes (1 m × 1 m and 2 m × 2 m). Results: The germination rate showed a significant difference according to the sowing date. In addition, several sunflowers survived in plots with a high germination rate, which also led to a higher flowering rate. We found that the smaller the plot, the smaller the area available for inter-species competition, and the higher the number of surviving sunflower plants. The relative dominance and importance value of the species varied significantly between the sowing dates; in particular, sunflowers sown in March could compete with wild plants for longer than those sown on other sowing dates. Conclusions: These observations indicate that the potential for invasiveness of sunflowers differs depending on the environmental conditions and seed density at the time of release.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.211-211
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• 2022

Amaranth is a nutritious and broadly adapted seed crop in high demand around the world. A preliminary approach for understanding the genetics of amaranth resources entails a morphologic characterization, which can provide the basis for breeding the first variety in Korea, leading to satisfying the needs of farmers and consumers. Therefore, this study aimed to evaluate the phenotypic characteristics of ten genetic amaranth accessions for the selection of outstanding accessions in terms of yield and grain quality. A randomized complete block design was used, with fifteen replications for each accession under field conditions. Five quantitative and three qualitative descriptors were evaluated with descriptive analysis. The results showed that the accessions with plant heights smaller than the average (>112.7 cm) presented lower yields and smaller seed sizes, thus decreasing the grain quality. The cluster analyses established groups of accessions with good yields (>30.1 g of seeds per plant) and stable morphological characteristics. Based on yield and morphological descriptors, the proposed selection index indicated four accessions as potential parents for amaranth breeding programs in Kora.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.243-247
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• 2003

To examine ideal leaf types with higher $\textrm{CO}_2$ assimilates and different seed sizes, 12 soybean varieties were planted on the pot in a plastic house covered with glass. Leaf function based on stomatal conductance and $\textrm{CO}_2$ assimilation in soybean is different in seed size and leaflet shape. Mean $\textrm{CO}_2$ assimilation of a single leaf was 19.66 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$ and showed higher in small seed cultivars with narrow leaflet than that of small seeds with wide leaflet (18.29 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$), but within large seed groups, it was higher in wide leaflets (19.17 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$) than narrow leaflet cultivars (17.45 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$). In small seed and narrow leaflet cultivars, stomatal conductance ranged from 0.14 to 0.15 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$, while $\textrm{CO}_2$ assimilation ranged from 19 to 20 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$. The Photosynthetic rate was closely related to stomatal conductance, transpiration and water use efficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.123-128
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• 1986

The characteristics such as characters of seed, fruit and endosperm, development of embryo, dehisced and germination rate of seeds which harvested at 10 days intervals from 20 days to 60 days after pollination were determined to clarify the optimum time for seed production of ginseng. The sizes of length, width and thickness of fruits, seeds and endosperms investigated on 20 days after pollination were not largely different from those that harvested after 60 days. But the weights of fruits and seeds were increased along with the delay of harvesting time. The seeds which harvested from 30 to 60 days showed comparatively high dehisced and germinated rates, especially 40 days in dehisced rates and 50 days in germinated rates. The embryos were rapidly grown in early stage. Lengths of the embryo on 20 days after pollination were approximately grown to 30 ${\mu}{\textrm}{m}$. And after 30 days pollinated, embryos were not only more rapidly grown to 213 ${\mu}{\textrm}{m}$ but also cotyledon premodia were developed in this time and completely formed after 40 days.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.87-96
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• 2010

This study was performed to evaluate the planting properties of herbaceous plant and cool-season grass in porous polymer blocks that were manufactured by using recycled coarse aggregates and unsaturated polyester resin to develop environmentally friendly planting blocks. Unsaturated polyester resin, natural and recycled coarse aggregates and $CaCO_3$ were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes(5-10 and 5-20mm). Tests for the void ratio and compressive strength of porous polymer concrete were performed at curing age 7 days. Also, porous polymer block using recycled coarse aggregates were applied to kinds of plants such as tall fescue, Perennial ryegrass, Lesedeza and Alfalfa. After seed, initial germination, germination ratio, cover view and growth length for planting blocks were estimated by various methods.

• Agricultural and Biosystems Engineering
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• v.5 no.2
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• pp.55-59
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• 2004

This study aimed to develop a seeder for sowing large seeds such as those of fruit vegetables used as rootstocks in grafting. It investigated how the nozzle diameter and the nozzle's vacuum pressure affected the seeding performance. This study found that a nozzle diameter of 1.5 mm was capable of sowing most of the seed sizes used in this study. The highest seeding rates for 'Chambak', 'Tuktozwa', and 'Hukjong' were $97.6\%$, $98.8\%$, and $97.6\%$, respectively. Lineup status after sowing was good. The working performance was 75.6 sheets/hr. An average seeding rate of 1 grain was $97.8\%$.

• Journal of the Korean Ceramic Society
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• v.52 no.3
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• pp.197-203
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• 2015

The colorization of $Zn_2SiO_4$ crystal glazes was investigated by adding nucleating seeds with various coloring agents. The addition of color fixing agents such as $Fe_2O_3$, $MnO_2$, and NiO with seeds caused changes in the colors of glazes. The crystallinity and crystal size were dependent on glaze composition and firing schedules. By controlling coloring agents and firing schedules, it was possible to create various colors and sizes of crystals in a zinc-based crystalline glaze.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.260-264
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• 2011

Leaf structure is one of the important agronomic traits. A rolled leaf mutant was induced from an ethyl methane sulfonate (EMS)-treated japonica rice, 'Koshihikari'. The rolled leaf mutant showed phenotypes of reduced leaf width and leaf rolling. In addition, several abnormal morphological characteristics were observed, including dwarfism, defected panicle, delayed germination, and lower seed-setting. Microscopic analysis revealed that the number of small veins was decreased and the sizes of adaxial bulliform cells were reduced in the mutant leaves. The genetic study with two $F_2$ populations from the crosses of the rolled leaf mutant with 'Koshihikari' and Milyang23 suggested that the mutant phenotype might be controlled by a single dominant gene.

• Animal cells and systems
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• v.5 no.2
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• pp.101-106
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• 2001

AFLPS (amplified fragment length polymorphisms) were used to estimate the genetic diversity of seven populations of Brassica campestis L. ssp. napus var. nippo-oleifera Makino between naturalized and cultivated populations. The seven Korean populations maintained a high level of genetic diversity. For example, all eight primers were high polymorphic, with an average of 3.2 effective alleles per primer set, and the expected heterozygosity was also high. The majority of genetic variance resided within populations The combinations of an insect-pollinated, outcrossing breeding system, large populations sizes, a high degree of gene flow and a propensity for high fecundity may explain the high level of genetic diversity within cultivated populations. Estimates of genetic similarity on the proportion of shared fragments ranged from 0.952 to 0.999. The high level of gene flow In Korean naturalized populations is mainly caused by seed dispersal via sea tide and the gene flow of cultivated populations may be enhanced in part by artificial pollen dispersal.