• Title/Summary/Keyword: Magnesium

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Effect of Magnesium Sulfate on Sisomicin Fermentation (Sisomicin 발효에 대한 Magnesium Sulfate의 영향)

  • 한상헌;신철수
    • Microbiology and Biotechnology Letters
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    • v.20 no.2
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    • pp.213-218
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    • 1992
  • Fermentation patterns were changed by adding magnesium sulfate to the fermentation broth and its effect on enhancement of sisomicin production was investigated. When cell growth was expressed by DNA content, trophophase and idiophase were separated, but not by dry cell weight. On the other hand, addition of magnesium sulfate had the antibiotic accumulated inside the cells be liberated into the outside, and this effect resulted in improving the final antibiotic yield. The maximum antibrotic yield was obtained when 100 mM magnesium sulfate was added after one day of cultivation, and enhanced more than three times compared to that of the control to which it was not added.

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Inhibitory Effects of Magnesuim Carbonate on Cytotoxicity, Genotoxicity, Mutagenicity, and Cell Transformation by Nickel Subsulfide (Nickel Subsulfide의 세포독성, 유전독성, 변이원성 및 세포변이에 대한 Magnesuim Carbonate의억제효과)

  • 하은희;홍윤철;윤임중
    • Environmental Mutagens and Carcinogens
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    • v.19 no.1
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    • pp.20-27
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    • 1999
  • In order to know the inhibitory effect of magnesium carbonate(MgCO3) on cytotoxicity, DNA damage, mutagenicity, and cell transforming ability of nickel subsulfide, the inhibition of cell proliferation, DNA-protein crosslinks formation (DPC), HGPRT point mutation, and cell transformation were evaluated. Nickel subsulfide(Ni3S2) and magnesium carbonate as insoluble compounds were used for this study. BALB/3T3 cell, CHO-K1 cell, and C3H10T1/2 cell were used in this experiment. Exposure concentration of nickel subsulfide was 1 $\mu\textrm{g}$/ml. The concentrations of magnesium carbonate in this study were 0.6 $\mu\textrm{g}$/ml, 1.2 $\mu\textrm{g}$/ml, 2.4 $\mu\textrm{g}$/ml and the molar ratio of magnesium to nickel when exposed simultanously were 0.5, 1.0 and 2.0 respectively. The results were as follows; 1. Magnesium carbonate reduced the inhibitory effect of nickel subsulfide on cell proliferation. 2. Magnesium carbonate also reduced the effect of nickel subsulfide on DNA-protein crosslinks formation. 3. HGPRT point mutagenicity of nickel subsulfide was reduced when magnesium carbonate treated simultaneously. 4. Magnesium carbonate reduced cell transforming ability of nickel subsulfide. Conclusively, nickel subsulfide showed cytotoxicity, cell transforming ability, and mutagenicity strongly and magnesium carbonate may have protective roles in these nickel effects.

Design and Analysis of vehicle Hood using Magnesium Alloy Sheets (마그네슘 합금 판재를 이용한 차량용 후드의 설계 및 해석)

  • Shin H. W.;Yoo H. J.;Yeo D. H.;Shin K. Y.;Koh Y. S.;Choi S. W.;Lee S. W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.220-226
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    • 2005
  • To achieve the weight reduction of a vehicle, Magnesium alloys are widely used in automobile parts because of its lightweight characteristics. Magnesium alloys also have advantages in recycling, stiffness, NVH , heat protection. But Magnesium alloy parts are mainly manufactured by diecasting processes, their productivity was not so high compared to by sheet metal working. We are developing vehicle hood using magnesium sheets. In this study we designed magnesium alloy hood which have equivalent mechanical characteristics to steel hood. Using finite element method we decided thickness of magnesium sheets under some design requirements and we changed the shape of hood inner panel and hinge reinforcements. Outer and inner panel thickness was 1.3mm, 1.5mm respectively. Panel dentibility analysis was performed to conform the new magnesium design by nonlinear FEM package. Formability and hemming of Magnesium sheets are the subjects for further study because they have poor stretchability compared to steel sheets.

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Experimental Study on the Combustion Characteristics of Magnesium using Infrared Thermography and FE-SEM (적외선 열화상법 및 FE-SEM을 활용한 마그네슘 연소특성에 관한 실험적 연구)

  • Lee, Jun-Sik;Nam, Ki-Hun
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.6_2
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    • pp.927-934
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    • 2020
  • Magnesium powder has been widely used in various industries because it is light weight and extremely high mechanical strength including aeronautics and chemicals. However, magnesium, as a combustible metal, poses serious safety issues such as fires and explosions if it is not managed properly. Especially, magnesium's max adiabatic flame temperature is 3,340℃ and it is impossible to extinguish it by using water, CO2 and Halonagents. The aim of this study is to identify the combustion characteristics of magnesium powder. We carried out a combustion experiment, using 1 kg of magnesium (purity > 99 %, particle < 150 ㎛). The features of the magnesium burning process were scrutinized using infrared thermal image analysis. Also, a field-emission scanning electron microscope (FE-SEM) were used employed to analyze particulate composites and properties. It concludes the significant tendency of magnesium fire and light, combustion carbide's particle characteristics. This study contributes to make better prevention and response manners to magnesium fires, as well as fire investigation measures.

Study on the Distillation of Magnesium Alloy Scrap (마그네슘 합금 스크랩의 진공증류에 관한 연구)

  • Wi, Chang-Hyun;Yoo, Jung-Min;Jang, Byoung-Lok;You, Byoung-Don
    • Korean Journal of Metals and Materials
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    • v.46 no.1
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    • pp.13-19
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    • 2008
  • To develop a recycling process of magnesium alloy scrap, a fundamental study on the distillation of magnesium alloy melt was carried out. Melt temperature, vacuum degree and reaction time were considered as experimental variables. The amount of vaporized magnesium melt per unit surface area of melt increases with the increase of melt temperature, reaction time and vacuum degree. The vapor condensed at the tip of water cooling Cu-condenser as a form of pine cone. Magnesium and zinc were vaporized easily from the melt. However, It's difficult to separate magnesium and zinc by vacuum distillation because vapor pressure of zinc is similar to one of magnesium. The contents of aluminum, manganese and iron, etc. in residual melt increase due to the decrease of magnesium and zinc content after the distillation of magnesium alloy.

Evaluation of Mechanical Properties for AZ31 Magnesium Alloy(1) (AZ31 마그네슘 합금 판재의 기계적 특성 평가(1))

  • Won S.Y.;Oh S.K.;Osakada Kozo;Park J.K.;Kim Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.53-56
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    • 2004
  • The mechanical properties and optical micrographs are studied for rolled magnesium alloy sheet with hexagonal close packed structure(HCP) at room and elevated temperatures. Tensile properties such as tensile strength, elongation, R-value and n-value are also measured for AZ31 magnesium alloy. Magnesium with strong texture of basal plane parallel to the rolling direction usually has high R-value and plastic anisotropy at room temperature. As temperature increases, the R-value for AZ31 magnesium sheet decreases. In addition, the AZ31 sheet becomes isotropy and recrystallization above $200^{\circ}C$. Formability of magnesium alloy sheets remarkably poor at room temperature is improved by increasing temperature. Sheet forming of magnesium alloy is practically possible only at high temperature range where plastic anisotropy disappears.

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Biodegradation of Secondary Phase Particles in Magnesium Alloys: A Critical Review

  • Kannan, M. Bobby
    • Corrosion Science and Technology
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    • v.15 no.2
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    • pp.54-57
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    • 2016
  • Magnesium alloys have been extensively studied in recent years for potential biodegradable implant applications. A great deal of work has been done on the evaluation of the corrosion behaviour of magnesium alloys under in vitro and in vivo conditions. However, magnesium alloys, in general, contain secondary phase particles distributed in the matrix and/or along the grain boundaries. Owing to their difference in chemistry in comparison with magnesium matrix, these particles may exhibit different corrosion behaviour. It is essential to understand the corrosion behaviour of secondary phase particles in magnesium alloys in physiological conditions for implant applications. This paper critically reviews the biodegradation behaviour of secondary phase particles in magnesium alloys.

Shrinkage Strain Property of the Magnesium Oxide Matrix According to Magnesium Chloride Addition Ratio (염화마그네슘 첨가율에 따른 산화마그네슘 경화체의 길이변화 특성)

  • Jung, Byeong-Yeol;Lee, Sang-Soo;Song, Ha-Young
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.11a
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    • pp.150-151
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    • 2013
  • Recently, the internal space organization of the building changes to the frame construction and flat slab construction in the wall type structure. And the use of light weight panel changing the internal joint use easily is increased. Therefore, in this research, the length change characteristic that the magnesium chloride addition rate reaches to the magnesium curing body tries to be studied. It could confirm according to the length change specific result that the magnesium chloride amount of addition reaches to the magnesium oxide curing body to expand. And the thing described below was the large-scale expansion the magnesium oxide addition rate 60%. And it showed up as 50, 40, 30, 20, and order of 10s (%). It could look at to form the hydrate of the SEM picture result needle-shaped of the Hardened.

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The Role of Magnesium and Calcium in Eggshell Formation in Tsaiya Ducks and Leghorn Hens

  • Shen, T.F.;Chen, W.L.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.2
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    • pp.290-296
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    • 2003
  • Tsaiya ducks and Leghorn hens are the two major laying birds raised in Taiwan. They are all excellent egg layers. Tsaiya ducks are small in body size (1.3 kg) with bigger egg weight (65 g) and stronger eggshell breaking strength than eggs from hens. The eggshell consists mainly of calcium carbonate, hence calcium plays an important role in the eggshell formation. Magnesium is also present in eggshell in small amounts, which may have effect on maintaining eggshell quality. In comparison studies, it was shown that the duck eggshells contained higher calcium and lower magnesium content than chicken eggshells. The eggshell magnesium content was not affected by the dietary magnesium levels (690-2380 ppm) in ducks, but in hens, it increased linearly with dietary magnesium levels. The palisade layer ($5000{\times}$) of the eggshell was found to have a compact form for ducks while there are many hallow vesicles in chicken eggshells. The eggshell magnesium deposition model is different for ducks and hens with ducks having a one-peak and hens having a two-peak model. The calcium deposition model is similar for both birds. Both the carbonic anhydrase specific activity and total activity in the shell gland mucosa of ducks are higher than those in hens. Ducks retain higher magnesium and lower calcium in the shell gland mucosa and secret less magnesium and more calcium into the shell gland lumen for eggshell deposition. The ATPase specific activity is maintained fairly constant during the eggshell forming stage, indicating continuous calcium transport into the shell gland lumen for eggshell formation. The magnesium content in duck eggshells is much lower than that in hens indicating that the magnesium content in the eggshell may have an effect on eggshell quality.

Precipitation of Magnesium Sulfate from Concentrated Magnesium Solution for Recovery of Magnesium in Seawater (해수 중 마그네슘 회수를 위한 마그네슘 농축액으로부터 황산마그네슘의 석출)

  • Cho, Taeyeon;Kim, Myoung-Jin
    • Resources Recycling
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    • v.25 no.4
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    • pp.32-41
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    • 2016
  • The precipitation test, which is the last step of magnesium recovery process consisting of three processes (pre-precipitation, selective dissolution of magnesium, precipitation) is performed to obtain magnesium sulfate powder from seawater. In the study, we succeed in precipitating the magnesium sulfate by adding acetone into the solution of magnesium over 4 times concentrated from seawater. The yield efficiency of magnesium sulfate increases with increasing pH and the ratio of added acetone. More than 99% of magnesium is obtained as magnesium sulfate hydrate ($MgSO_4{\cdot}6H_2O$) under the following conditions; pH 1.0 ~ 1.5, and the ratio of solution and acetone 1 : 1.5 (v:v). The acetone used in the precipitation process is recovered by the fractional distillation.