• Journal of Plant Biology
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• v.27 no.3
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• pp.191-214
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• 1984

Investigations were performed on the flora, community composition and ecology of the diatoms collected from the water system in the suburbs of Kyungju city from June, 1981 to May, 1982 and from August to September, 1983. Total taxa of 157 were identified as diatoms consisting of 2 orders, 5 suborders, 8 families, 12 subfamilies, 26 genera, 97 species, 54 varieties and 6 forma. Among them 69 taxa were found as unreported ones in Korea. By the creteria of adaptability of these taxa to organic pollution in water, the taxa could classified as 8 of tolerant, 34 of indifferent and 115 of intolerant taxa.

• Journal of Plant Biology
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• v.3 no.2
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• pp.26-28
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• 1960

Electron-Microscopical Observalion on Fine Structure of Diatom Frustules which is collected in the East Coast of Kyung-Pook Province. Kor. Jour. Bot. 3(2) 26-28 lllus. 1960 The fine structure of Diatom frustules which is collected in the east coast of Yungil and Wul Sung, Kyung-Pook Province, is ovserved by the light microscope and hte electron-microscope, and the materials collected by auther are 1 family, 2 genus and 2 species. Coscinodiscus elegans. Greville Actinoptychus undulatus Rals Those were havitated in sea water as the plankton which were found in diatomite.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.625-630
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• 2010

This study aims to examine the possible use of heavy oil fly ash as raw material for deodorization panels by adding additives such as activated carbon and diatomite during deodorization panel manufacturing process and improving the performance of formaldehyde and toluene elimination.The recycled heavy oil flyash deodorization panel to be used either of them as additives removed more than 93% of formaldehyde and more than 97% of toluen but the compressive strength was decreased 27 to 63%. In an experiment to be used both additives, Whereas, the panel to include activated carbon 5% and diatomite 5% removed 84% against formaldehyde and 96% against toluen, and the compressive strength was increased 32% better than standard panel. Therefore it could be confirmed that the recycled heavy oil flyash deodorization panel is increased the compressive strength and the removal efficiency against harmful chemical substances by using the additives mixture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.312-319
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• 2017

For high value-added applications of natural blue diatomite, the physical refining process and synthesis of SiC from refined diatomite were investigated. Approximately 30 percent Fe ($Fe_2O_3$) in raw blue diatomite was removed by a particle sieve separation process; the Fe composition for 325 mesh down powder was approximately 2 percent. Although a wet and/or dry magnetic separation process had some influence on the separation and/or refining of Fe composition, the Fe composition in the non-magnetic by-product was approximately 2 percent. Water leaching separation was effective in removing the Fe composition; approximately 40 percent of the Fe in raw blue diatomite was removed. The synthesis of ${\beta}$-SiC by a carbothermal reduction of the $SiO_2$ in the refined diatomite using carbon (graphite, carbon black), the effects of an acid-treatment on removing the Fe, and the specific surface area for the synthesized powder were also investigated. The impurities were mostly eliminated and the specific surface area was increased to $52.5m^2/g$.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.705-708
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• 2008

Diatomite, bentonite and zeolite were used as porous materials for fabricating hygroscopic panels. Moisture adsorption and desorption of porous materials were investigated and hydrothermal method was applied to fabricate panels. Cheolwon diatomite and Pohang zeolite showed excellent characteristics of moisture adsorption and desorption. These characteristics were caused by higher surface area and pore volume of porous materials. Moisture adsorption contents were influenced by surface area and pore volume of panels, and surface area more effected on moisture adsorption. Moisture adsorption content of panel with 10% Pohang zeolite was 180g/m$^2$and that of 10% Cheolwon diatomite was 170g/m$^2$. Moisture desorption content of panel with 10% Pohang zeolite was 105g/m$^2$. Moisture adsorption contents of panel with porous materials were higher than that of panel without porous materials.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.63-69
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• 2010

This study investigates the chemical resistance of the recycled aggregate concrete containing calcined ground slag, fly ash, and diatom powder. The recycled aggregate which had the density of $2.48g/cm^3$, the absorption of 4.25%, and standard gradation was used and the concrete specimens were submerged in solutions of $Na_2SO_4$ and $CaCl_2$ at 10% concentration for 6 months. As the submersion result, pore volume of over $0.02{\mu}m$ diameter was formed less in the concrete specimens containing calcined ground slag, fly ash, and diatom powder than in the concrete without the pozzolanic materials and the result shows the effectiveness of the pozzolanic materials for the increase of chemical resistance of the recycled aggregate concrete.

• Korean Journal of Ecology and Environment
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• v.38 no.4 s.114
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• pp.494-502
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• 2005

Antialgal bacteria and ciliates were tested alone and in combination for their abilities to decrease the densities of the warm-weather cyanobacterium, Microcystis aeruginosa, and the cold-weather centric diatom, Stephanodiscus hantzschii. Our results indicate that the density of M. aeruginosa was effectively suppressed by the bacterium, Streptomyces neyagawensis, and the heterotrich ciliate, Stentor roeselii. However, co-treatment with both bio-agents stimulated the algal density rather than decreasing it, suggesting that S. neyagawensis and S. roeselii may have an antagonistic relationship. Additional experiments revealed that the density of S. hantzschii was effectively suppressed by the bacterium, Pseudomonas putida, and by the above mentioned strain of S. roeselii. Co-treatment with both bio-agents had a higher antialgal activity than treatment with each alone, indicating that the bio-agents may act synergistically. These results suggest that the anti-alge efficacy of co-treatment with multiple biological control agents is likely to differ depending on the bio-agents and target organisms.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.311-319
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• 2008

To understand the relative immigration activities (RIA) of hibernal diatom community in Lake Ilgam (at the station with and without macrophyte) and River Han (at the station with different current and nutrient), a natural and artificial bed substrate was deposited from 15 to 29 January 2008. For the study period, both waters comprised huge biomass of diatom, over 75% of total abundance. Nutrients in water column, ash-free dry matter (AFDM) and chlorophyll-a (Chl-a) concentration in substrates were decreased with increasing of current in rivers, while in lakes the macrophyte largely affected the diatom community and water quality. Algal RIA in rivers was high at stations with high concentration of nutrient, AFDM and Chl-a, and in high nutrients and no macrophytes in lakes, respectively. The species showing a higher RIA was Nitzschia amphibia in rivers and Aulacoseira italica in lakes, while the dominant species were Navicula sp. in rivers and Syndera acus in lakes, suggesting no relationship between water algal biomass and its RIA. These results suggest that the RIA of stream diatom community depends exclusively on the current, while the planktonic diatom in lake was of the macrophyte.

• Magazine of the Korea Concrete Institute
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• v.9 no.1
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• pp.143-151
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• 1997

Chemical resistance of the cement mortar containing the Thermally Activated Diaomite(TAD) and H.M.(Heavy Metals) has been studied. The H.M.. extracted from EAF(Electrica1 Arc Furnace) Dust. were saturated with diatomite. The diatomite was then thermally activated at $750{\circ}C$ for 30minutes and powdeled. The powder was mixed with a portland cement on a weight basis from 0%. 2.5%. 5.0%. 10%. 20%. The optimum mixture. after those mixtures were subjected to compressive strength(7 and 28days) and leaching bchaviour of H.M.. was tested for its experiment on Wet/Dry cycles and chemical resistance(e.q. imrncrsion in 5%(Conc.) of H2S04, CaC12 and hlgSO4. It was shown that the cement, mortar containing 10% of' P.D. gave a rise to the remarkable increase in compressive strength. The compressive strength was generally decrease beyond the addition of 10% of P.D. The maximum $496kgf/cm^2$ of 28days compressive strength was acheiveti when 10% of P.D. was added to the cement mortar.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.181-187
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• 2005

For 4 years (2000 ${\sim}$ 2003), annual fluctuations of standing crops of cyanobacteria and physicochemical factors were examined at five sites from Bridge of Seungsoo to Bridge of Seungsan in the lower part of Han River. The cyanobacterial abundance (ND to 4,167 cells $mL^{-1}$) was strongly decreased during the heavy rains in every year. During the similar periods in 2003, cyanobacteria hardly observed, and comprised below of 10 percentage of total phytoplankton. In the period of little cyanobacteria, some green algae and diatom dominated the phytoplankton community, while the concentration of chlorophyll a has not largely change. These results indicate that heavy frequent precipitation strongly limited the growth of cyanobacteria, and lead an algal succession by the appearance of new algal groups.