• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.E1
• /
• pp.27-34
• /
• 2006

Although the importance of size-resolved raindrops study has been known, it has not been popularized up to the present. In the present study, an attempt was made to generalize the size-resolved raindrops study by a combination of the frozen raindrop collection method and a commercially available high-performance capillary electrophoresis (HPCE). Samplings were carried out at Kyoto, Japan in October 2002. The inorganic ions (chloride, nitrate, sulphate, calcium, ammonium, sodium, magnesium, potassium) in size classified raindrop samples were successfully analyzed by HPCE with good repeatability. To assure the accuracy and precision of HPCE data, t-test was conducted with paired analytical data, which were experimentally constructed by analyzing standard solutions with HPCE and IC, respectively. T-test showed that there is no notable difference between the concentrations determined by the two analytical methods. Every ionic concentration in both cation and anion was found to be strong raindrop size dependence. Though there was slight increase of sodium and sulphate concentrations between 0.85 mm and 1.15 mm raindrop radius, it showed a strong decrease for every ionic component with increasing droplet radius. The combination of the frozen raindrop collection method and a commercially available HPCE can meet the need of size-resolved raindrops study.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.55 no.3
• /
• pp.35-40
• /
• 2013

The present study was conducted to investigate the adsorption potential of red mud for fluoride removal. Different operation parameters such as the effect of contact time, initial concentration, pH, competing anions, seawater, adsorbent dose amount, and adsorbent mixture were studied. Nearly 3 hr was required to reach sorption equilibrium. Equilibrium sorption data were described well by Langmuir model and the maximum adsorption capacity of red mud was 5.28 mg/g. The fluoride adsorption at pH 3 was higher than in the pH range 5-9. The presence of anions such as sulfate, nitrate, phosphate, and bicarbonate had no significant effect on fluoride adsorption onto red mud. The fluoride removal by red mud was greater in seawater than deionized water, resulting from the presence of calcium and magnesium ion in seawater. The use of red mud alone was more effective for the removal of fluoride than mixing red mud with other industrial waste such as oyster shells, lime stone, and steel slag. This study showed that red mud has a potential application in the remediation of fluoride contaminated soil and groundwater.

• Mycobiology
• /
• v.36 no.1
• /
• pp.28-33
• /
• 2008

Ganoderma lucidum (Fr.) Karst (Polyporaceae), belonging to basidiomycota, is one of the most famous medicinal mushrooms. This study was carried out to investigate favorable mycelial growth conditions, such as pH, temperature, growth media, carbon sources and nitrogen sources of Korean strains in G. lucidum. The most suitable temperature for the mycelial growth was obtained at $30^{\circ}C$. In general, optimal temperature range for the mycelial growth was found at $25{\sim}30^{\circ}C$. This Mushroom has a broad pH range ($5{\sim}9$) for its mycelial growth and mostly favorable growth was found at pH 5. Generally, Hamada, Glucose peptone, YM, Mushroom complete and Lilly media were the most suitable for the mycelial growth of G. lucidum. Among 10 different carbon sources, dextrin, galactose and fructose were best but the rest of other carbon sources also facilitated the growth of mycelia. The most suitable nitrogen sources were ammonium acetate, glycine, arginine and calcium nitrate, but to a certain extent, all of the supplemented nitrogen sources also stimulated the mycelial growth.

• Advances in nano research
• /
• v.4 no.4
• /
• pp.295-307
• /
• 2016

The present research work reports a low temperature ($40^{\circ}C$) chemical precipitation technique for synthesizing hydroxyapatite (HAp) nanoparticles of spherical morphology through a simple reaction of calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate at pH 11. The crystallinity of the single-phase nanoparticles could be improved by calcinating at $600^{\circ}C$ in air. Thermogravimetric and differential thermal analysis (TG-DTA) revealed the synthesized HAp is stable up to $1200^{\circ}C$. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) studies confirmed the formation of spherical nanoparticles with average size of $23.15{\pm}2.56nm$ and Ca/P ratio of 1.70. Brunauer-Emmett-Teller (BET) isotherm of the nanoparticles revealed their porous structure with average pore size of about 24.47 nm and average surface area of $78.4m2g^{-1}$. Fourier transform infrared spectroscopy (FTIR) was used to confirm the formation of P-O, OH, C-O chemical bonds. Cytotoxicity and MTT assay on MG63 osteogenic cell lines revealed nontoxic bioactive nature of the synthesized HAp nanoparticles.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.3
• /
• pp.109-115
• /
• 2002

Mycelial growth of L. edodes by pretreatments of softwood was studied on a sawdust medium. The sawdust used was from the following softwood species : Larix leptolepis, Pinus densiflora and Pinus koraiensis. The pretreatment consisted of cold-water (48 h), hot-water (3 h) and steam extractions (3 h) at a ratio of 500 g : 3,000 mL (sawdust : distilled water). The sawdust medium was a mixture of 76% sawdust, 20% rice bran, 3% glucose, 0.4% potassium nitrate and 0.6% calcium carbonate. Following sawdust pretreatments proved most suitable : L. leptolepis (steam extraction), P. densiflora (hot-water extraction) and P. koraiensis (hot-water extraction). Mycelial growth on P. koraiensis sawdust increased in proportion to an increase in hot-water extraction time. Mycelial growth was optimum on the sawdust extracted for 12 hours, hot-water extraction beyond this period proved unsuitable. With the exception of P. densiflora at 100 ㎍/mL, antifungal activity occurred in every sample. Maximum inhibition of mycelial growth was obtained from following concentration of hot-water extractives : P. densiflora (10⁴ ㎍/mL) and P. koraiensis (10⁴ ㎍/mL). This study has provided useful preliminary information for the cultivation of L. edodes.

• Journal of the Korean Chemical Society
• /
• v.4 no.1
• /
• pp.18-26
• /
• 1957

There are two problems to be solved by our efforts in the enamel frit. One is how we can cover the enamel frit thin with complete milk white as possible, and the other is how it can be, made resistant for chemicals than before one. The frit which can solved the two problems just mentioned above is titanium enamel frit. This frit has been developed in America after War Ⅱ, and now the research for concerning antimony frit into titanium frit is under development entirely. In order to develope the enamel industry in Korea, it is urgent problem to convert antimony frit into titanium frit. By the way the titanium frit is emulsified titanium oxide crystal which made through reheating the supersaturated solution of titanium oxide in the basis of glass. Unfortunately, there are many obscure points in active fact or which influence on its composition and characteristics yet. However, this task was tried for the first in Korea. As first step, the test was carried on the reference books, and we can be possible convert antimony frit into titanium frit as a result of this experiment. As a conclusion, for the purpose of developing the enamel industry in Korea, we studied that the research for converting antimony enamel frit which has been used popularly into titanium enamel frit which is more economic and resistant for chemicals. As a result of experiments, the following points concerning with titanium frit have become clearly. 1. It is better when the composition of titanium enamel frit has as following table.Man Duck San Silica 24 An Yang Feldspar 20 Borax 28 Sodium Nitrate 4 Cryolite 7 Calcium Carbonate 3.6∼1 Titanium Oxide 10 Calcium phosphate 0 ∼3.2 Calcium Fluoride 0∼1.8 Antimony Oxide 0∼0.5 2. The amount of $TiO_2$, to be added is $10%\;to\;12{%,\;CaF_2\;is\;under\;1.8%,\;P_2O_5\;is\;under\;1.6%,\;Sb_2O_3\;is\;under\;0.5%$. 3. In the titanium frit, the limit of iron oxide amount to be included is under 0. 5%. 4. Comparing the titanium enamel frit with antimony enamel frit not only the titanium frit can be savely 20.6% in the price of raw materials, but one time of glazing and heating process is omitted in each case, and it is known the titanium frit is more resistant for chemicals than antimony frit.

• Korean Journal of Soil Science and Fertilizer
• /
• v.32 no.1
• /
• pp.22-30
• /
• 1999

This experiment was carried out to determine the forage yield and mineral contents of silage corn(Zea mays L.), and N balance, soil chemical characteristics and nitrate-N level in infiltration water by different types and N rates of liquid manure applied. Seven treatments consisting of chemical fertilizer $200kg\;N;ha^{-1}$, liquid cattle manure 200, 320 and $440kg\;N;ha^{-1}$, liquid swine manure 200, 320 and $440kg\;N;ha^{-1}$ were arranged in a randomized complete block design with three replications. The results obtained at National Livestock Research Institute, RDA, in Suweon from May 1997 to Aug. 1997 are summarized as follows : There were no significant differences in percentage of dry matter among the treatments, but significant dry matter yield differences were found (P<0.05), and also the mean dry matter yield of liquid swine manure plot was higher than that of liquid cattle manure plot. Potassium, calcium and magnesium contents of silage corn increased with increasing liquid manure application rates (P<0.05). Nitrate-N content of silage corn in the liquid cattle manure treatments was not influenced by liquid manure application rates, but that in the liquid swine manure treatments increased with increasing the N rates of liquid manure application. pH and contents of exchangeable canons of the soil after experiment were raised by increasing the amount of liquid manure application. Available $P_2O_5$ content in topsoil(0-10cm) was highest as $340mg\;kg^{-1}$ at the plot of liquid swine manure $440kg\;N;ha^{-1}$. Concentration of nitrate-N in infiltration water increased at the plot of liquid swine manure $440kg\;N;ha^{-1}$. Amount of nitrogen balance increased with increasing liquid manure application rates. Based on the results of this experiment, it is suggested that the mean dry matter yield of liquid swine manure plot was higher than that of liquid cattle manure plot, and the amount of nitrogen balance increased with increasing liquid manure application.

• Korean Journal of Weed Science
• /
• v.1 no.1
• /
• pp.57-68
• /
• 1981

To clarify the mode of uptake of butachlor (2-chloro-2', 6'-diethyl-N-(butoxymethyl) acetanilide) by rice seedlings, its phytotoxic action to growth and physiological activities, studies were conducted with rice seedlings, at the 6th or 7th leaf-stage, which were treated with nutrient solution containing butachlor 0, 1.8, 3.6, 7.2, 10.8 or 14.4 ppm for 1, 2 or 4 days, in other case, the solutions were thereafter renewed with the untreated nutrient solution for further growth. Uptake of butachlor by rice seedlings increased linearly with increase of its concentration and duration of uptake. Butachlor inhibited root growth more than shoot growth, furthermore, the inhibitory effect on the shoot growth was greater in height than in weight or leafing rate. After 4 day-treatment, the rates of shoot growth in weight were delayed for 4 days. Butachlor inhibited water uptake rapidly and linearly with increase of its external concentration. The reduced uptake of water was followed by slow increase in the stomatal resistance of leaves. Upon completion of butachlor treatment, rate of water uptake was recovered rapidly, but the stomatal resistance with lag in time. Butachlor did not affect the uptake of cation such as ammonium, potassium and calcium, but inhibited substantially uptake of nitrate in proportion to its concentration. Especially, butachlor did not affect synthesis and degradation of nitrate reductase. In addition, butachlor has shown much greater binding to the lipidic substances from rice roots than the proteinous material. The primary mechanism of phytotoxic action of butachlor does not seem to be its effect on the protein synthesis, but great affinity to membranes. The inhibition of water uptake, and its subsequent closure of stomates is thought very important for reduced growth under mild phytotoxicity.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.4
• /
• pp.293-303
• /
• 2017

To elucidate the physiological responses of rice plants to the essential mineral silicon (Si), we assessed the effects of treatments with Si, nitrogen ($NH_4NO_3$; ammonium nitrate), and calcium ($CaCl_2$; calcium chloride), independently or in combination on mineral uptake rates and levels of the hormones abscisic acid (ABA), gibberellin ($GA_1$) and jasmonic acid (JA). We found that nitrogen and calcium uptake was inhibited by Si application. However, solo application of nitrogen or calcium did not affect Si uptake. Compared to the untreated plants, the application of Si, $NH_4NO_3$ or $CaCl_2$ increased the endogenous hormone levels in treated plants. In particular, the concentrations of $GA_1$ and JA increased significantly after the application of Si or $NH_4NO_3$. The level of $GA_1$ observed after a treatment (solo or combine) with Si, and $NH_4NO_3$ was higher than that of the control. By contrast, independent application of $CaCl_2$ or a combined treatment with Si and $CaCl_2$ did not alter $GA_1$ levels. The highest level of $GA_1$ was present in plants given a combination treatment of Si and $NH_4NO_3$. This effect was observed at all time points (6 h, 12 h and 24 h). Endogenous JA contents were higher in all treatments than the control. In particular, a combination treatment with Si and $NH_4NO_3$ significantly increased the JA levels in plants compared to other treatments at all time points. A small increase in JA levels was observed after 6 h in plants given the $CaCl_2$ treatment. However, JA levels did not differ between plants given a $CaCl_2$ treatment and controls after 12 h or 24 h of exposure. We conclude that treatment with $CaCl_2$ alone does not affect endogenous JA levels in the short term. Endogenous ABA contents did not show any differences among the various treatments.

• Journal of Bio-Environment Control
• /
• v.4 no.2
• /
• pp.144-151
• /
• 1995

This experiment was carried out to investigate the effect of different nutrient solution temperatures on the growth and quality of welsh onion in winter season. The fresh weight increased with the increase of temperature within the range of 13-23$^{\circ}C$. The top length was longer 18 and 23$^{\circ}C$ than at 13$^{\circ}C$, the dry weight was the highest at 18$^{\circ}C$. The potassium content in plant was the highest at 18$^{\circ}C$, calcium and magnesium contents were higher at 13 and 18$^{\circ}C$ than at 23$^{\circ}C$. The vitamin C content decreased with the increase of nutrient solution temperature, but there was no statistical significance within treatments. The pyruvic acid was higher at 13 and 18$^{\circ}C$ than at 23$^{\circ}C$, while nitrate content was lower at 13 and 18$^{\circ}C$ than 23$^{\circ}C$. Therefore, for growth and quality of welsh onion, it was concluded that 18$^{\circ}C$ may be suitable nutrient solution temperature in winter season.