• Korean Journal of Ecology and Environment
• /
• v.33 no.3 s.91
• /
• pp.244-250
• /
• 2000

Algal growth potential (AGP) bioassay were conducted to assess the water quality and fertility in the Kum River from March 1998 to June 1999. AGP values were always the highest at the conjuction site of the Kapchon, which is a tributary of the Kum River. Average value of AGP by Microcystis aeruginosa in the main river and tributary was 17.0 mg dw/l, 48.3 mg dw/l, respectively. AGP values decreased towards the lower part of the river and consisted in the water quality or nutrient analysisresults. Among the tributaries, AGP of the Kapchon, Mihochon and Soksongchon were relatively high, and the average value was 161.2, 50.3 and 125.6 mg dw/l, respectively. AGP value in the Yukuchon was lowest among the study stations with <2.7 mg dw/l. Water quality in the lower part of the Kum River deteriorated in drought season, and the AGP values of this season were higher than those in other seasons. Based on correlation analysis between AGP results and nutrients, limiting nutrient appeared to be P because SRP (r = 0.99) was higher than other nutrients, and N uptake in algal growth was preferred by $NH_4$ rather than $NO_3$. The variation of AGP was different according to localities and seasons, and it was related to nutrient fluctuation in the inlet tributary. Water quality status according to AGP was assessed to be eutrophic.

• Applied Chemistry for Engineering
• /
• v.24 no.1
• /
• pp.44-48
• /
• 2013

In this work, we have prepared tungsten doped vanadium oxide ($W-VO_2$) particles with a low phase transition temperature. $W-VO_2$ particles were synthesized via thermolysis method using vanadyl (IV) sulfate and ammonium bicarbonate as precursors. The structure and thermochromic property of synthesized $W-VO_2$ particles were investigated by FE-SEM, EDS, XRD, XPS, and DSC analysis. The prepared $W-VO_2$ showed a nearly platy morphology, which indicates that the tungsten was successfully doped in the crystal lattices of $VO_2$. $W-VO_2$ nanoparticles with the size of 60 nm exhibited a monoclinic crystal structure and its chemical composition and surface state were also likely to be close to that of $VO_2$. In addition, the phase transition temperature of $W-VO_2$ was $38.5^{\circ}C$, which was approximately $29.2^{\circ}C$ lower than that of pure $VO_2$ ($67.7^{\circ}C$), indicating that the prepared sample had a good reversible thermochromic stability.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.14 no.4
• /
• pp.233-238
• /
• 1981

A recirculating water system without filter bed was used for a high density experimental rearing of common carp, Cyprinus carpio, during the summer of 1981. Of the water system, 3 tanks were used for stocking each tank with 10,000, 20,000 and 30,000 common carp fingerlings which averaged 0.6 g. The water in the system was maintained in dark green colour by heavy growth of phytoplankton during the most period of the experiment. In this experiment, the best daily growth rate, $3.7\%$, was obtained from the 10,000 fish group followed by $2.8\%\;and\;3.0\%$ from the 20,000 and 30,000 fish groups respectively. Thus there was no significant difference between the latter two groups. Especially, notably high concentration of total ammonia, $5\sim7$ ppm ammonia-N, in the culture water appeared during the most experimental period, but this did not seem to have affected feeding and growth of the fish when the water was kept at heavy bloom. It was also obvious that the outbreak of columnaris disease was effectively depressed in this green water recirculating system compared to that in clarified recirculating system. One tank ($7m^2$) of this system was stocked with 446 common carp of intermediate size averaging 352.2 g and after 40 day rearing they grew to 486.3 g in average with a daily growth rate of $0.8\%$. This result was a little inferior to that reared in a tank of the clarified water system as control which showed $1.0\%$ daily growth rate. Therefore, before an initiation of the commercial production of fish in this method, further studies concerning the amount of ammonium with its effect on the fish under rearing in this system and the columnaris disease problem should be carried out.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.10 no.1 s.20
• /
• pp.69-73
• /
• 2004

Control if Sediment is very important in prawn farm due to the eruption of toxic materials such as unionized $H_{2}S,\;NH_{3}\;and\;NO_3$. In this study, column test was conducted with filter media such as activated carbon, zeolite, oyster shell and iron chloride to evaluate the reduction of toxicity from sediment. ammonia-N($NH_3$) was effectively removed by Zeolite and oyster shell. It was indicated that ammonium ion($NH_4^+$) was removed by ion exchange of zeolite. And the ammonia in the column of oyster shell was existed as the form of $NH_4^+$, which is not toxic for prawn because oyster shell was stably kept at $8{\sim}9g$ of pH. Therefore, some of ammonia($NH_4^+$) was removed by oyster shell. Hydrogen sulfide and COD were effectively removed by adsorption of activated carbon and a partial removal of hydrogen sulfide was accomplished by Oyster shell. Phosphorous was removed by activated carbon, oyster shell and iron chloride. In prawn farm, the concentration of ammonia was increased with increase of pH by algae photosynthesis in the column of activated carbon, zeolite and iron chloride, but it was revealed that pH was stably kept in the column of oyster shell.

• Korean Journal of Medicinal Crop Science
• /
• v.20 no.2
• /
• pp.101-107
• /
• 2012

Effects of nitrogen (N), phosphorous (P) and potassium (K) on the shoot and bulb growth of wild garlic ($Allium$ $victorialis$ var. $platyphyllum$) were studied by adopting $in$ $vitro$ culture. These macronutrients influenced the growth of both the shoot and bulb of garlic depending upon their application doses. A minimum of 3% potassium nitrate ($KNO_3$) as a source of nitrogen was found to be critical for shoot elongation while higher concentrations were inhibitory. Garlic bulb growth was profuse on the usual $KNO_3$ strength and sucrose (7%), followed by $KNO_3$ (9.4 mM) supplement. On providing 41.22 mM ammonium nitrate ($NH_4NO_3$) as nitrogen source highest shoot growth was observed while 82.45 mM $NH_4NO_3$ as a source of nitrogen supported high bulb growth. With regard to potassium a good shoot growth was observed in medium that contained 0.31 mM $KH_2PO_4$ and 3% sucrose, while bulb growth was high on 2.5 mM $KH_2PO_4$ and 7% sucrose. These experiments may thus direct the development of excellent growth conditions for the commercial production of edible wild garlic.

• Korean Journal of Microbiology
• /
• v.30 no.5
• /
• pp.391-396
• /
• 1992

Anabaena variabilis A TCC 29413. a photoautotrophic and nitrogen fixing cyanobacteria. was investigated on the environmental factors regulating the growth and nitrogen lixation activity. A good growth of cyanobacteria] cells was observed due to nitrogen t1xation by the heterocyst differentiation in nitrogen free Allen and Arnon (]/8) medium. The nitrogenase activity was appeared to be in proportion to the cell growth lor 6 days then drastically decreased in the later growth period when the nitraTe was accumulated to high level in the culture to cause the inhibition. The optima] conditions lilr the cell growth and nitrogenase activity of A. varillbili.l were anaerobic. IO.OO0 lux. $30^{\circ}C$ and pH 8 with the nitrogen Cree minimal medium. The activity was significantly inhihited by the low concentrations of ammonium and nitrate. but was stimulated b) the ]ow Ieve] of phosphate and carbonate sources. The treatments of several toxic heavy metals showed strong inhibition of the cell growth and nitrogenase activity by O.3~10 ppm in the order of $Hg^{2+}$ > $Cd^{2+}$ > $Co^{2+}$ > $Zn^{2+}$ > $Ph^{2+}$, and the concentrations for 50% inhibition of the maximum activity were 0.41. 0.47. 0.5 L 0.66 and 8.1 ppm. respectively. The addition of carbohydrates (0.5~ 1.0%) in the dark condition stimulated the growth and activity in the order of sucrose > fructose > glucose.

• Korean Journal of Microbiology
• /
• v.39 no.3
• /
• pp.148-154
• /
• 2003

Moraxella sp. CK-l is known to inhibits the growth of Anabaena cylindrica, a cyanobacterium. It has been documented that the ability of this growth inhibition of Anabaena cylindrica was attributed to extracellular autolysin from Moraxella sp. CK-l. However, it remains to be elucidated identification and characterization of autolysin have yet been elucidated. In this study, we tried to purify and identify autolysin secreted from Moraxella sp. CK-l. Cells were grown in a complex liquid medium (BGC-11) and culture supernatants were collected, followed by ammonium sulfate fractionation. Fractions were further separated with anion exchange column, Mono-Q, in FPLC system and analyzed by SDS/PAGE. The fraction containing high autolysin activity showed a single distinct protein peak in anion column and molecular mass of about 17 kDa in SDS/PAGE. Nterminal amino acid sequencing of the protein was analyzed, of which result showed the homology with some proteases, including extracellular serine protease, Dichelobacter nodosus.

• Korean journal of applied entomology
• /
• v.16 no.3 s.32
• /
• pp.149-154
• /
• 1977

Effect of Simazine(2-chloro-4,6-bis (ethylamino)-s-triazine), Nitrofen (2, 4-dichloro-4' -nitrodi­phenylether), Propanil (:3, 4-dichloropropionanilide), and Butachlor (2-chloro-2, 6-diethyl N-(buthoxy­menthyl) acetanilide on urea hydrolysis and subsequent nitrification was investigated in an upland soil incubated at $20\pm1^{\circ}C$. 1. All the herbicides tested had no effect on the hydrolysis of urea to ammonia at the recommended rates. Butachlor, at ten and fifty times the recommended rate, and Nitrofen, at fifty times the recommeded rate, depressed urea hydrolysis, resulting in reduction of ammonia. But the depressive effects were temporary, disappearing soon. Simazine and Propanil had no detrimental effect on urea decomposition at all the treated rates. 2. Also, all the chemicals tested had no effect on the nitrification process at the recommended rates. At higher concentrations of ten and fifty times the recommended rate Butachlor and Nitrofen inhibited the oxidation of nitrite, and propanil long inhibited the oxidation of ammonium to nitrite, but was inactive against nitrite oxidizer. These inhibitive effects of the chemicals, however, disappeared in the later period of incubation. Simazine had no effect on the nitrification process at all the treated rates. 3. The trend of change in soil pH of both the treated and untreated plots well reflected the change of soil nitrogen forms during incubation. No direct effect of the chemicals on soil pH was obserbed.

• Korean Chemical Engineering Research
• /
• v.54 no.2
• /
• pp.152-156
• /
• 2016

Experimental research on the preparation of photocatalyst for the decomposition of brilliant blue FCF ($C_{37}H_{31}O_9N_2S_3Na_2$) was performed. $TiO_2$ and ZnO powders were prepared from titanium (IV) sulfate and zinc acetate at low reaction temperature and atmospheric pressure by hydrothermal precipitation method without calcination. In addition, $TiO_2$ was prepared with cationic surfactant CTAB (Hexadecyltrimethyl ammonium bromide) at the same conditions. The physical properties of prepared $TiO_2$ and ZnO, such as crystallinity, average particle size and absorbance, were investigated by XRD, Zeta-potential meter and DRS. And, the photocatalytic degradation of brilliant blue FCF has been studied in the batch reactor under UV radiation. For the photocatalysts prepared without CTAB, $TiO_2$ has smaller particle size and larger absorbance and photocatalytic reaction rate than ZnO. And $TiO_2$, prepared with CTAB whose concentration is 1/10 of that of precursor, shows 15% higher than that prepared without CTAB in final photocatalytic degradation ratio of brilliant blue FCF.

• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.1
• /
• pp.39-45
• /
• 1998

As a basic research for developing a sludge application technique in forestry, this study was conducted to investigage a reasonable amount and period of sludge to be applied onto forest nursery of Acer palmatum Thunb. The paper mill sludge was used for the study, and ammonium nitrate was treated to some of them to reduce the C/N ratio lower than 40. The maximum amount of applied sludge was 7ton/ha/year, and they were spread on spring and on late summer. The sludge application did not stimulate early growth of the trees during a year. Since there was no significant changes in soil chemical properties, the amount of applied sludge was thought to be too little to result in a significant role for tree growth. However, the soil water showed significant increase of Cu when the activated sludges were applied during late summer. Thus, the time of application need to be determined cautiously with considering the risk of ground water contamination. In conclusion, if we set a goal from the view point of long-term concept such as forest productivity rather than to get a short-term product, the uncomposted sludge in small amount during growing season might be considered to be applied on forest nursery.