• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.490-498
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• 2012

This study demonstrates the investigation of zooplankton communities (e.g. rotifers, cladocerans and copepods) and environmentally related driving factors (e.g. elevation, area size, water depth, types of dike construction, and bottom substrates). We hypothesized that zooplankton community structure and composition would be influenced by ambient driving forces in different scales of the irrigation ponds (Dumbeong). A total of 66 zooplankton species/groups (56 rotifers, 9 cladocerans, 1 copepods) were found and identified at 45 Dumbeong of Goseong region (i.e. Goseong-gun) in 2011. The rotifers occupied 84.9% of the total zooplankton abundance. We could categorize a clear separation of zooplankton communities into 4 different patterns based on cluster analysis. Zooplankton diversities in Dumbeongs were lower than those in natural ponds or wetlands. In addition, community structure of zooplankton was also simpler and had a broken stick distribution based on SHE analysis. Species composition in each Dumbeong was not significantly discriminated each other. The result of canonical correspondence analysis (CCA) pinpointed that significant influential variables upon zooplankton community were dissolved oxygen percent saturation, pH, and Dumbeong's material. This study indicated that morphological type of the Dumbeong and its water quality could determine the community structure of zooplankton. Furthermore, the connectivity between ambient habitats and materials could be necessary to be rigorously considered in respect to producing the Dumbeongs to subsidize alternative habitats for wetland ecosystem in freshwater landscape.

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.507-513
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• 1997

To separate and concentrate functional components contained in soybean curd whey, ultrafiltration was performed using regenerated cellulose or polysulphone membrane of spiral-wound type with MWCO 10,000, and the permeate and retentate solutions were analyzed. As the pH of soybean curd whey increased, the permeate flux decreased in both membranes. Treatment of 0.01 M EDTA rather decreased the permeate flux compared with control. The concentration of ionic calcium, which decreased with the pH increase, was thought to affect the permeate flux also. In case of polysulphone membrane, the permeate was efficiently purified and the retentate protein was concentrated significantly in which the membrane rejection value (MRV) for chemical oxygen demand (COD) was 79.25% and that of protein was 98.42% at the volume concentration ratio (VCR) of 10. MRV of the protein of regenerated cellulose membrane was lower than that of polysulphone membrane. To recover oligosaccharides to the permeate solution and increase the content of raffinose and stachyose, regenerated cellulose membrane was more suitable than polysulphone membrane and the optimum VCR was 4.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.207-217
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• 1992

In this study, isolated and cultured nitrogen fixed microbes were seeded in the three-phase fluidized bed in which gas, solid and liquid were contacted directly. Input velocity was varied from 8.12 cm/hr to 16.32 cm/hr. And upflow gas pressure was fixed to 80 psi. Return ratios were from 0.2 to 0.6 with the each experimental condition. According to these condition, movement of media, growth of biofilm and removal efficiency were measured. As the results, in case of briquette ash, biofilm was developed to $170{\mu}m$ when velocity was 8.12 cm/hr and return ratio was 0.6. In this condition, COD removal efficiency was 97% and $NH_4$-N removal efficiency was 83%. At the same condition, biofilm thickness of glass bead was $17.59{\mu}m$ and its COD and $NH_4$-N removal efficiency was 83% and 72%. Nitrogen fixed microbes have following characters: it formed dark-brownish sludge, excellent adhesive force, easy solid-liquid separation and low oxygen uptake ratio, but sensitive to DO concentration. Not only it endured shock loading, but required short time to steady state.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.123-130
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• 2020

Submerged Membrane bioreactor (SMBR) is one of the last techniques that allow a high quality of treated industrial effluents by coupling biological treatment and membrane separation. Thus, this research was an effort to evaluate performance of a SMBR treating a model textile wastewater (MTWW). Different SMBR operating parameters like mixed liquor suspended solids (MLSS) and Dissolved oxygen concentration, hydraulic retention time (HRT), and nutrients addition (N and P) have been investigated. MTWW (influent to the SMBR) was generated using the reactive azo-dye, Novacron blue FNG (100mg/L feed concentration). Results of MTWW treatment using SMBR under optimal operating conditions (MLSS, 4.2-13.3g/L; HRT, 4 days; pH, 6.9-7.2; conductivity, 400-900 μS/cm and temperature, 19.4-22.2 ℃) showed that COD and blue colour treatment performances are between 94-98% and 30-80%, respectively. It is concluded that SMBR can be used in large scale textile wastewater treatment plants to improve effluent quality in order to meet effluent discharge standards.

• Resources Recycling
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• v.22 no.2
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• pp.37-43
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• 2013

Unlike the conventional slurry type wire sawing, the diamond wire sawing method adopts diamond plated wire as sawing media instead of slurry consisted of both silicon carbide and oil. Wafering with diamond plated wire leaves solid element of the sludge mostly made up of silicon, and it is not difficult to recover 95% or more of silicon by a simple separation process of oil from the sludge. In this study, silicon was recovered from the sludge by drying process and organic and metal impurities were removed by sintering process. As result 3N grade silica was obtained successfully by thermal processing utilized the fact that the recovered silicon readily combines with oxygen due to fine particle size.

• The Korean Journal of Zoology
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• v.13 no.3
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• pp.75-84
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• 1970

Gamma-radiolyses of oxygenated and deoxygenated glycylglycylclycine in aqueous solution and in the solid state are observed, with special regards to peptied bond rupture for elucidation of radiolytic mechanism of proteins, by means of chromatorgraphic separation of degradation products, spectrophotometric quantitation of carbonyl compounds, micro-titration of amide formation, infrared spectrophptometry, and ultraviolet spectrophotometry for evaluation of radiation damage. Essential difference of peptide bond rupture is observed in solution and in the solid state, being high in the former and negligible in the latter. On the other hand, the presence of and obsence of oxygen in solution during irradiation are not so significant with respect to peptide bond rupture, except the recombination of free-radicals produced in deoxygenated solution. Peptide bond rupture in solution is attributable to the mechanisms proposed by Garrison et al.; dehydrogenation followed by hydrolysis to yield acid amide and carbonyl function as found on the basis of radiolytic products. Peptide bond attack at $\\alpha$-carbon locus might be suggestive for irradiated solid but not significant in view of low degree of peptide bond rupture.

• The Korean Journal of Nuclear Medicine
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• v.19 no.1
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• pp.137-143
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• 1985

Using chelating agents such as Nitrilotriaceticacid(NTA), ticacid(DTPA) and Ethylenediaminenitrilotetraceticacid(EDTA), with TC-99m were determined in vitro and in vivo. Methods.of separation and determination of TC-99m-liposomes added chelating agents were practiced by thin layer chromatogram scan and gel filtration. Biodistributions of Tc-99m-liposomes in normal and sarcoma 180 cells bearing mice were observed. The results were as follows: 1) Maximum amount of $Sn^{+2}$ to reduction from pertechnetium$(10\sim20{\mu}ci)$ by adding 0, 1, 10 and $100{\mu}g$ of $SnCl_2$ in 0.2 ml of oxygen free water was $10{\mu}g$. 2) The large amounts of $SnCl_2$ were not changed but the small amounts of $SnCl_2$ were much changed by labeling with TC-99m to add chelating agents. EDTA in small amounts of $SnCl_2$ were reduced more strongly than DTPA or NTA. Using a hydrophilic chelate, DTPA, the uptake of liposomes could not accumulated in liver and spleen by a lipophilic chelate NTA were significant in vivo. 3) Uptake by tumor was achived 1.14% of injected dose per gram tissue and tumor to organ ratios were measured in low with TC-99m-NTA-liposomes(+).

• Environmental Engineering Research
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• v.25 no.4
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• pp.536-544
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• 2020

To address organic dye wastewater, economic and effective adsorbents are required. Here, magnetic biochar from alkali-activated rice straw (AMBC) was successfully synthesized using one-step magnetization and carbonization method. The alkaline activation caused the large specific surface area, high pore volume and abundant oxygen-containing groups of the AMBC, and the magnetization gave the AMBC a certain degree of electropositivity and fast equilibrium characteristics. These characteristics collectively contributed to a relative high adsorption capacity of 53.66 mg g^-1 for this adsorbent towards rhodamine B (RhB). In brief, RhB can spontaneously adsorb onto the heterogeneous surface of the AMBC and reach the equilibrium in 60 min. Although the initial pH, ionic strength and other substances of the solution affected the adsorption performance of the AMBC, it could be easily regenerated and reused with considerable adsorption content. Based on the results, H-bonds, π-π stacking and electrostatic interactions were speculated as the primary mechanisms for RhB adsorption onto the AMBC, which was also demonstrated by the FTIR analysis. With the advantageous features of low cost, easy separation, considerable adsorption capacity and favorable stability and reusability, the AMBC would be a potential adsorbent for removing organic dyes from wastewater.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.207-216
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• 2005

Spawning behaviors of Squalidus gracilis majimae (Cyprinidae) were observed in the laboratory whose environmental factors such as light (D/L = 16 : 8), temperature ($20\;{\sim}\;24\;＾{\circ}C$), and dissolved oxygen (>8 mg $L^{-1}$) were quite regularly controlled. The behavioral patterns were categorized into three stages ofpre-spawning, spawning, and Post-spawning behaviors. In Particular, the pre-spawning stage was specified by 11 specific behavioral patterns of aggressive mating behaviors. During the spawning stage, the male and female performed four distinct spawning behaviors including sexual temptation, stimulation, egg spawning, and the separation, and randomly laid about 200 ${\sim}$ 300 eggs on the bottom substrates through the night. After finishing spawning, two adults separated toward their refuges and showed 3 types of post-spawning behaviors such as the resting, occasional eggs protecting, and the egg eating. The fish was identified as a partial-parental care species after the spawning.

• Journal of the Korean Vacuum Society
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• v.7 no.1
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• pp.35-42
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• 1998

- The Si-$SiO_2$ interface of silicon on insulator (SOI) formed by 100 keV $O^+$ was ohserved using high resolution transmission electron microscopy (HRTEM), before and after annealing. The interface of as-implanted sample, ~$5\times 10^{17}\textrm{cm}^{-2}O^+$ implanted at $550^{\circ}C$ was very rough and it has many defectsoxide precipitate, stacking fault, coesite $SiO_2$ etc. However, the interface became flat by high temperature annealing at $1300^{\circ}C$ for 4 hour. It's roughness, observed by HRTEM, was comparable to the interface roughness of 3 keV $O_2^\;+$ ion beam oxide and -6 nm gate oxide formed by thermal oxidation.