• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.631-639
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• 2013

The removal of phosphate from surface water is becoming increasingly vital to prevent problems such as eutrophication, particularly near urban areas. Recent requirements to reduce high concentrations of phosphate rely on physicochemical methods and adsorbents that must be effective even under strict conditions. The phosphate removal efficiencies of two adsorbents, Fe-Mn-Si oxide and Fe-Mn oxide, were investigated and the data used to compare kinetics and isotherm models. The maximum adsorption capacities of the two adsorbents were 47.8 and 35.5 mg-$PO{_4}^{3-}/g$, respectively. Adsorptions in both cases were highly pH dependent; i.e., when the pH increased from 3 to 9, the average adsorption capacities of the two adsorbents decreased approximately 32.7 % and 20.3 %, respectively. The Freundlich isotherm model fitted the adsorption of Fe-Mn-Si oxide more closely than did the Langmuir model. Additionally, anionic solutions decreased adsorption because of competition with the anions in the adsorbing phosphate. Although affected by the presence of competing anions or a humic substance, Fe-Mn-Si oxide has better adsorption capacity than Fe-Mn oxide.

• Biomedical Science Letters
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• v.24 no.4
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• pp.357-364
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• 2018

Manganese (Mn) is used as main materials in various chemical processes of industry, but it suggested that Mn brings about its toxicant by fume or dust through respiratory system and skin barrier. Mn toxicant induces the loss of mental health and life quality by cerebrovascular and skin diseases. Nevertheless, it lefts much unknown on the mechanism and the effectively therapeutic methods about Mn toxicant. Therefore, this study was evaluated the cytotoxicity induced by manganese dioxide ($MnO_2$) in cultured NIH3T3 fibroblasts, and also, the correlation between $MnO_2$-induced cytotoxicity and oxidative stress was examined. While, the effect of Eclipta prostrata L. (EP) extract belong to Compositae was assessed against $MnO_2$-induced cytotoxicity in the view of antioxidative effect for searching the natural resources mitigating or preventing the $MnO_2$-induced cytotoxicity. In this study, $MnO_2$-induced cytotoxicity was revealed as mid-toxic by Borenfreud and Puerner's toxic criteria, and catalase (CAT), an antioxidant prevented $MnO_2$-induced cytotoxicity by the remarkable increase of cell viability in these cultures. While, in the protective effect of EP extract on $MnO_2$-induced cytotoxicity, EP extract effectively prevented the cytotoxicity induced by $MnO_2$ via antioxidative effects such as xanthine oxidase (XO) inhibitory ability and DPPH-radical scavenging ability. From the above results, EP extract showed the effective prevention against $MnO_2$-induced cytotoxicity correlated with oxidative stress by antioxidative effects. Conclusively, this study may be useful to research or development the alternatively therapeutic agent from natural resources like EP extract for the treatment of diseases resulted in oxidative stress.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.552-555
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• 1995

The magnetic properties of Mg-Mn ferrites were investigated in the composition range of $Mg_{a}Mn_{b}Fe_{c}O_{4\pm\delta}$ (a+b+c=3) with the addition of $Al_{2}O_{3}$. In $MgO-MnO-Fe_{2}O_{3}$ ternary system, the spinel single phase existed within the composition range of MgO-50 mol%, MnO-70 mol% and $Fe_{2}O_{3}-60\;mol%$. The saturation magnetic flux density increased with the increase of $Fe_{2}O_{3}$ content and showed the maximum at the stoichiometric composition of $(Mg,Mn)Fe_{2}O_{4}$. In $Mg_{x}Mn_{1-x}Fe_{2}O_{4}(x=0.2~0.8)$ system, the saturation magnetic flux density showed the maximum at $Mg_{0.2}Mn_{0.8}Fe_{2}O_{4}$. The addition of $Al_{2}O_{3}$ resulted in the decrease of saturation magnetic flux density but increased the electrical resistivity.

• Journal of the Korean Institute of Gas
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• v.4 no.2 s.10
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• pp.27-32
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• 2000

In this study, $Mn_3O_4$ was synthesized by the different equivalent ratios using solution of $MnCL_2 {\cdot} 4H_2O$ and NaOH. We have investigated the crystal structure and surface area by XRD, BET Method, studied on the decompositon and adsorption of carbon dioxide with synthesized $Mn_3O_4$. As the results, we surveyed that main peak was $Mn_3O_4$, some Peaks were $MnO_2$ and $Mn_5O_8$ The specific surface area was ranged from $13.92m^2/g$ to $32.33m^2/g$. The decomposition of $CO_2$ was observed by the differential equivalent ratios at $450^{\circ}C$. $CO_2$ was well decomposed at equivalent ratio of 0.75. The amount of chemisorption of $CO_2$ was ranged from 2.885 to 19.628cc/g. Optimal equivalent ratio was 1.00 for the chemisorption of $CO_2$.

• Child Health Nursing Research
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• v.2 no.2
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• pp.5-18
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• 1996

The purposes of this study were to measure the degree of perceived uncertainty and to identify the rearing attitudes of mothers with chronically ill children, and to examine the relationship between the perceived uncertainty and the rearing attitude of these mothers. The subjects of this study consisted of 133 mothers with chronically ill children, registered at 2 university hospitals in Seoul. Data was collected from April 1 to May 31, 1996. The Parents' Perception of Uncertainty Scale(28-item 4 point scale) and the Maternal Behavior Research Instrument (49-item 5 point scale) were used. Data was analyzed by Cluster analysis, ANOVA MANOVA and t-test. Results of this study are summarized as follows : 1. Mothers perceived their uncertainty to be slightly high (Mn 2.48). The degree of perceived uncertainty by the four components slightly differed unpredictability(2.72), lack in clarity(2.58), vagueness (2.52) and lack of information(2.04) . The degree of perceived uncertainty of mothers with ill children revealed to be influenced significantly by the age of the ill children, duration of illness after the diagnosis, and the experience of hospitalization. 2. Among the rearing attitudes : moderatlely high affective(Mn 3.98) and resrictive(Mn 3.58) attitudes of mothers toward their ill children were identified. Mothers tend to give positive evaluations of their childrens' behaviors (Mn 3.38) and less rejection(Mn 2.81). 3. Mothers' rearing attitude were correlated with the degree of perceived uncertainty in illness ; mothers in the Low Perceived Uncertainty Group (Mn 1.99) revealed the highest affective (Mn 4.08), the lowest resrictive(Mn. 2.72) attitudes and tendency to give positive evaluations of their childrens' behaviors (Mn 3.54) compared to the High Perceived Uncertainty Group(Mn 3.26) and Moderate Perceived Uncertaity Group(Mn 2.57). 4. The degree of perceived uncertainty, the duration of illness after the diagnosis and the experience of hospitalization revealed to be significantly influential to the rearing attitude of mothers with chronically ill children. From the above results, it can be concluded that predicting and controlling mothers' uncertainty are necessary for improved, efficient nursing interventions and normal growth & development of the chronically ill children.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.612-616
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• 2000

The effect of Co dopant on the (La, Sr)MnO3 cathode was investigated. La2Zr2O7 and SrZrO3 were formed as the reaction products between YSZ and LSMC. The reactivity of LSMC with YSZ increased with increasing Co content. However, the cathodic polarization resistance decreased with increasing Co doping. Therefore, doping Co at Mn site in the (La, Sr)MnO3 cathode was effective on controlling the polarization resistance of the cathode. The polarization property of LSMC-YSZ composite(60 wt%: 40 wt%) cathode was better than that of LSMC single cathode.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.711-714
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• 2002

The Ce, Mn: $LiTaO_3$ crystals were grown by Czochralski method in congruent ${\varphi}$3＂ $LiTaO_3$ single crystal growing conditions. Concentrations of Ce and Mn in melt were respectively 0.1 mole%. As-grown crystals were red, transparent and the grown crystals were tested with oxidation/reduction treatment for clor and other properties. Influence of Ce and Mn dopants on $LiTaO_3$ crystal properties was discussed. And the nonlinear optical properties of the Ce, Mn: $LiTaO_3$ crystal are being studied.

• Journal of Magnetics
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• v.18 no.3
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• pp.221-224
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• 2013

Electron paramagnetic resonance (EPR) spectra of $Mn^{2+}$ impurity ion in Stoichiometric $LiNbO_3$ single crystal (SLN) was investigated with an X-band EPR spectrometer in the temperature range of 3 K~296 K. The intensity of EPR spectrum of $Mn^{2+}$ ion was increased to 20 K and decreased again below 20 K as the temperature decreases. The zero-field splitting parameter D decreased as the temperature increases. It was suggested that $Mn^{2+}$ ion substitute for $Nb^{5+}$ ion instead of $Li^+$ ion. No changes for hyperfine interaction of $Mn^{2+}$ ion was obtained in the temperature range of 3 K~296 K.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.2
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• pp.105-114
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• 2004

This pot experiment was. conducted to investigate the effects of systematic variation application of Fe, Mn, Cu, and Zn on forage performance of orchardgrass and white clover. The treatments of systematic variation were 0/100, 25/75, 50/50, 75/25, and 100/0％ in the Fe/Cu(trial-1), Mn/Zn(trial-2), and Fe + Cu/Mn + Zn(trial-3), respectively. The treatments of Fe/Mn/Cu/Zn(trial-4) were composed of 70％ in main element and 10％ in other 3 elements, respectively. 1. In general, the unbalanced applications of Fe and Mn resulted in the Mn and Fe deficiencies(chlorosis) on white clover, respectively, because of the antagonism between Fe and Mn. In white clover, the traits of growth, root/nodule, and flowering, which were influenced by the systematic variation of Fe, Mn, Cu, and Zn, were closely correlated to each other. In the Fe/Cu trial, the 0/100 and 25/75 induced a Fe-deficiency on white clover, and the 0/100 also showed poor root growth and flowering. In addition, the 50/50 and 75/25 showed an early flowering of white clover. 2. In the Mn/Zn trial, the 0/100 induced a severe Mn-deficiency(chlorosis) on white clover. The 25/75 and 50/50, however, diminished the chlorosis symptom. The 75/25 and 100/0 showed generally good root growth and flowering of white clover. 3. In the Fe + Cu/Mn + Zn trial, the 0/100 induced a Fe-deficiency, and the 100/0 induced a Mn-deficiency on white clover, which were correlated to the poor root growth and flowering. The 75/25 showed good root growth and flowering of white clover. 1be flowering of white clover tended to be more influenced by the Fe + Cu than by the Mn + Cu ratios. 4. In the Fe/Mn/Cu/Zn trial, the Fe and Mn deficiencies on white clover, which were influenced by the Mn and Fe treatments, also occurred. The Cu and Zn-deficiency symptoms, however, were not recognized. General differences have been showed in the numbers of flowers as following orders; Zn > Cu > Mn > Fe - 70% treatments.

• Journal of the Korean Electrochemical Society
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• v.13 no.2
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• pp.103-109
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• 2010

$Li_4Mn_5O_{12}$ was synthesized by combustion method using $LiNO_3$, $Li(CH_3COO){\cdot}2H_2O$ and $Mn(CH_3COO)_2{\cdot}4H_2O$. $Li_4Mn_5O_{12}$ was obtained over $400^{\circ}C$, however, the sample calcined at $400^{\circ}C$ for any time was mixed phases of $Li_4Mn_5O_{12}$ and $Mn_2O_3$. $Li_4Mn_5O_{12}$ calcined at $400^{\circ}C$ for 5 h had larger first discharge capacity (41.5mAh/g) at 1C-rate for 3.7~4.4V than other calcined samples. Moreover, applying to hybrid capacitor, it had good discharge capacity (24.74 mAh/g or 10.46 mAh/cc) at 100 mA/g for 1~2.5 V and higher energy density (39Wh/kg or 16.49Wh/cc) at same condition.