• The Korean Journal of Ecology
• /
• v.19 no.5
• /
• pp.375-383
• /
• 1996

Effects of forest fire on soil nutrients in pine forests were studied in Dosong, Kangwon Province in Korea. Soil samples were collected from burned sites and unburned sites (control) at Kusungri, Sampori and Wunbongri. Soil pH in burned sites was higher than that in unburned sites. Soil organic matter did not differ significantly between the burned and unburned sites. Concentrations of available phosphorus in burned soils were about 3 times higher than those in unburned sites. Also, concentrations of ammonium nitrogen were markedly increased in burned sites contrary to those of nitrate nitrogen. Total nitrogen, however, showed no significant difference between the sites. Concentrations of cations, calcium and magnesium, in burned sites were also significantly increased. Thus, even though forest fire removed the aboveground biomass of pine forests, inorganic nutrients added from ash may play a great role for growth of sprouts and seedlings after forest fire.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.160-160
• /
• 2013

Dye-sensitized solar cells (DSSCs) have attracted much attention because of their moderate light-to-electricity conversion efficiency, easy fabrication, and low cost. At present, platinum (Pt) is used as a counter electrode in DSSCs. However, it is found that Pt dissolves in iodide electrolyte solutions and creates chemical compound such as PtI4 and H2PtI6. Carbon based materials are one of candidates for a counter electrode of DSSCs. We prepare two types of graphite oxides by different chemical treatments; original graphite oxide, hydrazine treated graphite oxide. Each graphite oxide and magnesium nitrate dispersed in deionized water are prepared as solutions for electrophoretic deposition (EPD). Each graphite oxide electrode is deposited on fluorine-doped tin oxide (FTO) substrate by EPD method. Structural and electrochemical properties of each electrode are investigated by field-emission scanning electron microscopy and electrochemical impedance spectroscopy, respectively.

• Journal of Biosystems Engineering
• /
• v.28 no.4
• /
• pp.335-342
• /
• 2003

A simple disposable thick-film potentiometric strip has been developed and evaluated for hydroponics application. The strip consisted of low ion-selective electrodes (ISE) fabricated by screen-printing technology. The electrochemical responses of ion sensors for nitrate, ammonium, potassium, and magnesium were measured with specially designed 16-channel low voltage signal transducers. The analytical characteristics of the sensors were comparable with those of conventional ISE sensors. The thick-film sensors exhibit linear relationships over five concentration decades. The concentration of N $O_3$ - ion in standard solution can be determined by direct potentiometric measurements without any conditioning before measurements. However, measurement of $K^{+}$, N $H_4$$^{+}$, and $Mg^{2+}$ ionic concentrations in nutrient solutions seems not feasible.

• Journal of Environmental Science International
• /
• v.12 no.10
• /
• pp.1061-1069
• /
• 2003

The adsorption behaviors of strontium and cesium ions on fly ash, natural zeolites, and zeolites synthesized from fly ash were investigated. The zeolites synthesized from fly ash had greater adsorption capabilities for strontium and cesium ions than the original fly ash and natural zeolites. The maximum adsorption capacity of synthetic zeolite for strontium and cesium ions was 100 and 154 mg/g, respectively, It was found that the Freundlich isotherm model could fit the adsorption isotherm. The distribution coefficients (K$\_$d/) for strontium and cesium ions were also calculated from the adsorption isotherm data, The distribution coefficients decreased with increasing equilibrium concentration of strontium and cesium ions in solution. By studying the removal of cesium and strontium ions in the presence of calcium, magnesium, sodium, potassium, sulfate, nitrate, nitrite, and EDTA (in the range of 0.01 - 5 mM) it was found that these coexistence ions competed for the same adsorption sites with strontium and cesium ions.

• Microbiology and Biotechnology Letters
• /
• v.10 no.1
• /
• pp.15-26
• /
• 1982

A potential fungal lipid producer from starch, which was identified as Muror plumbeus, was isolated from natural sources and its optimum cultivation condition for lipid production was investigated. The Mucor plumbeus FRI 0007 showed the highest felt weight and lipid content which were 2.09 $\pm$ 0.24g per 50$m\ell$ of medium and 37.43% on dry weight basis respectively after 20 days incubation on the medium containing 21% of starch as a carbon source. The urea was the best nitrogen source as compared with sodium nitrate, potassium nitrate, magnesium nitrate, ammonium nitrate and ammonium acetate and its optimum concentration was 2.14g/$\ell$, showing 2.39 $\pm$ 0.07 g felt/50$m\ell$ of medium and 50.73% lipid content on dry weight basis after 25 days incubation. Besides the starch as a carbon source and urea as a nitrogen source, the Mucor plumbeus FRI 0007 utilized ZnSO$_4$, MgSO$_4$, NaH$_2$PO$_4$, $K_2$SO$_4$and FeCl$_3$as mineral sources. However, it did not require ail the above 5 minerals in group in-dispensably for its growth and lipid accumulation. The lipid and economic coefficient of Mucor plumbeus FRI 0007 grown on the medium containing 0.44g $K_2$SO$_4$or 5.00g MgSO$_4$/$\ell$solely were 14.96 and 15.37 and 31.12 and 26.10 which was higher than those on the medium containing the above 5 minerals.

• Journal of Marine Life Science
• /
• v.8 no.2
• /
• pp.150-159
• /
• 2023

To determine the toxic effects of the mirror carp, Cyprinus carpio nudus on waterborne nitric acid exposure, they were exposed to waterborne nitric acid at 0, 4, 20, 100, 500, and 2,500 mg NO₃^-/L for 96 h. The semi-lethal concentration (LC₅₀) of the scented fish by 96 hours of acute exposure to nitric acid was 1,433.54 mg NO₃^-/L. The physiological changes of waterborne nitric acid exposure on mirror carp were evaluated through hematologic properties, and RBC count showed a significantly decreased (p < 0.05). The change in the ion control ability of the mirror carp according to exposure to waterborne nitric acid was evaluated through the plasma inorganic component, and calcium and magnesium were significantly decreased (p < 0.05) in the plasma inorganic component. The health and stress status of the mirror carp due to exposure to waterborne nitric acid were evaluated through plasma organic ingredients, and the plasma organic component glucose showed a significantly increase (p < 0.05). Changes in liver damage and enzyme activity due to waterborne nitric acid exposure were evaluated through plasma enzyme components, the enzymatic activities of plasma AST, ALT, and ALP were significantly decreased (p < 0.05) in high levels of waterborne nitric acid exposure. The results of the present study suggest that waterborne nitric acid exposure to C. carpio nudus can toxicly affect survival, hematologic properties, and plasma components.

• 한국해양학회지
• /
• v.5 no.1
• /
• pp.14-29
• /
• 1970

Tidal variations of various chemical constituents in the laver bed sea waters in Wan Do Gun were determined over one spring tidal cycle from Oct. 1968 to Feb. 1969. Total ranges and means of the contents at Pyung-il Do and Wan Do are as follows. Although the average monthly variations of each content at Pyung-il Do were similar to those at Wan Do, most of the contents at Pyung-il Do were at a slightly higher level than at Wan Do. The values of silicate-silicon, phosphate- phosphorus and soluble iron, however, showed high levels at Wan Do. Chlorinity, magnesium, calcium, dissolved oxygen, silicate-silicon and phosphate-phosphorus contents increased from Oct. 1968 to Feb. 1969, though the content of soluble iron decreased before December and slightly increased in January and February. The average monthly variations of ammonia-nitrogen and nitrate-nitrogen contents were irregular. The nitrite-nitrogen content appeared in trace amounts in the months with a comparatively high water temperature, i.e., October and November, but in midwinter it was undetected. The ranges of the tidal variations of the contents of each chemical constituent were not significantly wide, though the contents varied excessively by the hour, and this may show the irregularity of the water quality in Wan Do Gun coastal area. As a rule, no regular tidal variation of the chlorinity was observed except slightly decreased value at ebb tide at Wan Do. In general, although the pattern of the variations of calcium and magnesium contents were similar to that of the chlorinity, no definite relationships between these constituents and chlorinity were observed. Tidal variations of the dissolved oxygen content, nutrient salts and soluble iron were irregular.

• Membrane and Water Treatment
• /
• v.8 no.4
• /
• pp.381-393
• /
• 2017

The inorganic components in tobacco sheet extract have significant influence on the sensory taste of the cigars and the harmful component delivery in cigarette smoke. To identify the contributions of the divalent inorganic components on harmful components delivery in cigarette smoke, a self-made selective electrodialysis was assembled with monovalent ion-selective ion exchange membranes. The influences of current density and extract content on the desalination performance were investigated. Result indicates that the majorities chloride, nitrate, and sulfate ions were removed, comparing with 50-60% of potassium and only less than 10% of magnesium and calcium ions removed in the investigated current density. The permselectivity of the tested cations across the Selemion CSO cation exchange membranes follows the order: $K^+>Ca^{2+}>Mg^{2+}$. A current density of $15mA/cm^2$ is an optional choice by considering both the energy consumption and separation efficiency. When the extract contents are in the range of 7%-20%, the removal ratios the potassium ions are kept around 60%, while the removal ratios of the calcium and magnesium ions fluctuate in the range of 16-27% and 8-14%, respectively. The tobacco smoke experiments indicated that the divalent metal ions have dual roles for the harmful component delivery in cigarette smoke. The divalent potassium and calcium ions were unfavorable for the total particulate matter emission but beneficial to decrease the HCN delivery in the mainstream cigarette smoke. The selective electrodialysis is a robust technology to decrease the harmful component delivery in cigarette smoke.

• Journal of the Korean earth science society
• /
• v.21 no.1
• /
• pp.81-92
• /
• 2000

The purpose of this study is to elucidate the characteristic of this study is of attitudinal variation of water quality for nine representative springs in the Halla mountain region. The evolutional processes of the spring water also have been studied. Results of hydrogeochemical analyses show that Gwaneumsa spring is very high in pH. The spring waters from Yungsil, Namguksunwon, Sungpanark Oremok and Gwaneumsa which springs situated lower than 1000m in altitude are relatively high concentrations in chloride, sulphate, nitrate nitrogen and sodium ions, indicating that they are affected by surrounding pollution sources. The concentrations of bicarbonate, sulphate and hydrogen ions in spring waters increase when the precipitation increases, whereas the concentrations of nitrate nitrogen, chloride and calcium ions decrease with increasing amounts of precipitation. The magnesium, sodium and electrical conductivity are nearly independent of the precipitation. The spring waters in the Halla mountain region belong to the groups of sodium or potassium type and bicarbonate type, except the Baegrogdam and Wiseorm spring water.

• Journal of Powder Materials
• /
• v.8 no.3
• /
• pp.151-156
• /
• 2001

MgO based nanocomposite powder including ferromagnetic iron particle dispersions, which can be available for the magnetic and catalytic applications, was fabricated by the spray pyrolysis process using ultra-sonic atomizer and reduction processes. Liquid source was prepared from iron (Fe)-nitrate, as a source of Fe nano-dispersion, and magnesium (Mg)-nitrate, as a source of MgO materials, with pure water solvent. After the chamber were heated to given temperatures (500~$^800{\circ}C$), the mist of liquid droplets generated by ultrasonic atomizer carried into the chamber by a carrier gas of air, and the ist was decomposed into Fe-oxide and MgO nano-powder. The obtained powders were reduced by hydrogen atmosphere at 600~$^800{\circ}C$. The reduction behavior was investigated by thermal gravity and hygrometry. After reduction, the aggregated sub-micron Fe/MgO powders were obtained, and each aggregated powder composed of nano-sized Fe/MgO materials. By the difference of the chamber temperature, the particle size of Fe and MgO was changed in a few 10 nm levels. Also, the nano-porous Fe-MgO sub-micron powders were obtained. Through this preparation process and the evaluation of phase and microstructure, it was concluded that the Fe/MgO nanocomposite powders with high surface area and the higher coercive force were successfully fabricated.