• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.383-386
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• 2008

Magnesium alloy sheets have been extending their field of applications to automotive and electronic industries taking advantage of their excellent light weight property. In addition to their excellent light property, magnesium alloys have several other advantages: high specific strength, good welding capability and corrosion resistance. Taking advantage of these benefits, magnesium alloys have also been substituting the polymeric materials in the electronic devices industries. In sheet metal forming application with magnesium alloys, the lower formability and high springback due to the lower elastic property (Young's modulus=45 GPa) at room temperature are major hurdles by which magnesium alloys have limited applications. In this study, commercial notebook case was adopted as the benchmark model, and then design parameters and process conditions are analyzed by the finite element simulation and physical try-outs.

• Advances in concrete construction
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• v.8 no.1
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• pp.39-45
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• 2019

Durability of strengthened reinforced concrete (RC) beams with CFRP sheets under wetting and drying cycles of magnesium sulfate attack is investigated in this research. Accordingly, 18 RC beams were designed and made where 10 of them were strengthened by CFRP sheets at their tension side. Magnesium sulfate attack and wetting and drying cycles with water and magnesium sulfate solution were considered as exposure conditions. Finally, flexural performance of the beams was measured before and after 5 months of exposure. Results indicated that the bending capacity of the strengthened RC beams was reduced about 10% after 5 months of immersion in the magnesium sulfate solution. Wetting and drying cycles of magnesium sulfate solution reduced the bending capacity of the strengthened RC beams about 7%. Also, flexural capacity reduction of the strengthened RC beams in water and under wetting and drying cycles of water was negligible.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.438-444
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• 2011

Magnesium is one of the abundant natural resources in the earth crust and seawater, which is directly related to various organisms activities interconnecting with water-rock system. In aqueous system, magnesium is known to predominantly exist in the form of $Mg^{2+}$ ion which is verified in its $E_h-pH$ diagram. When it is at equilibrium in aqueous system, temperature takes an essential role to complete equilibrium states. This study represents the change of the stable region of magnesium ion according to temperature, and how the consequences would affect aquatic organisms. It was revealed that there is a noticeable tendency shrinking the stable region of magnesium ion in a diagram as temperature increases, and as a result, aquatic bio-species presumably have difficulties to absorb the nutrient. Also, it was considered that the water system would be acidified by decreasing alkalinity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.11
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• pp.843-851
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• 2015

Among various ammonium salts and metal ammine chlorides used as solid materials for the sources of ammonia with solid SCR for lean NOx reduction, magnesium ammine chloride was taken up for study in this paper because of its ease of handling and safety. Lab-scale synthetic method of magnesium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%). To understand material characteristics for lab-made magnesium ammine chloride, DA, IC, FT-IR, XRD and SDT analyses were performed using the published data available in literature. From the analytical results, the water content in the lab-made magnesium ammine chloride can be determined. A new test procedure for water removal was proposed, by which the adsorption rate of lab-made sample was found to be approximately 100%.

• Microbiology and Biotechnology Letters
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• v.7 no.3
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• pp.165-173
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• 1979

Recovery component for cell division in UV-irradiated E. coli B was detected with use of the cell extract of E. coli B/r which is a resistant mutant of E. coli B against UV-irradiation. The active substance was non-dialyzable and increased the activity by adding B-NAD remarkably. One more factor for increasing or promoting the restoration recognized was magnesium. Magnesium was effective to stabilze the substance in procedure of isolation. Two active substances were obtained from sucrose gradient centrifugation. One of them was recovred from the botton area and the other from top area just below below surface. the former was not stabilized by magnesium, while the latter stabilized the activity by it remarkably. The former which did not require magnesium was insensitive to protease and the latter which required magnesium was sensitive to it. Both were insensitive to RNase and DNase. Recovery ratio was doubled by using nitrogen gas than aeration in purification process. DNA-ligase less mutant was revealed same activity on it's recovery ratio with the parent strain of E. coli K-12. The active substance stimulating the filament cell may exist as a complex which is inactivated easily in the dissociated state ana requrie B-NAD or magnesium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.601-607
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• 1996

Nineteen non-insulin-dependent diabetic(NIDD) and healthy control women were investigated to study the relationship between glycemic control and the level of calcium, zinc, and magnesium in the serum and urine. Urinary calcium, zinc and magnesium levels in the NIDD women were significantly higher(p<0.01) than those of the control women. There were no difference in serum magnesium and zinc levels between the two groups, but se겨m calcium level was lower(p<0.01) in the NIDD women compared to that of the control group. In the NIDD women, serum magnesium was negatively related to fasting blood glucose(r=-0.533 : p<0.05), urinary glucose(r=-0.767 ; P<0.001), urinary protein(r=-0.476 : p<0.05), and urine volume(r=-0.571 : p<0.05). The levels of zinc in both serum (r=0.515, p<0.05) and urine(r=0.623 : p<0.01) were related to urinary protein but only urinary zinc level(r=0.570 : p<0.01) was related to serum albumin. Urinary magnesium, not calcium was correlated with the urinary glucose(r=0.563 : p<0.05) and urinary protein(r=0.568 ; p<0.05). Fasting blood glucose was positively correlated with duration of diabetes, as well as dietary fat and calorie intake. The results of this study suggest that NIDD alters all magnesium, zinc, and calcium utilization, particularly magnesium is involved in glycemic control in this condition.

• The Korean Journal of Pain
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• v.30 no.3
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• pp.207-213
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• 2017

Background: Surgeon satisfaction and patient analgesia during the procedure of laparoscopic surgery are important issues. The aim of this work was to study if an intrathecal (IT) Bupivacaine combined with Magnesium sulfate may or may not provide good surgeon satisfaction in addition to improvement of intraoperative and postoperative analgesia. Methods: Sixty female patients were enrolled in this prospective, randomized, double-blind controlled clinical trial study. All patients were operated for gynecological laparoscopic surgery under spinal anesthesia. Patients were divided into two groups (Bupivacaine and Magnesium). Group Bupivacaine (30 patients) received intrathecal Bupivacaine 0.5% only (15 mg), while 30 patients in group Magnesium received intrathecal Bupivacaine (15 mg) in addition to intrathecal Magnesium sulfate (50 mg). The sensory block level, the intensity of motor block, the surgeon satisfaction, the intraoperative visual analog scale (VAS) for pain assessment, the postoperative VAS, and side effects were recorded during the intraoperative period and within the first 24 hours after surgery in the post-anesthesia care unit. Results: Surgeon satisfaction, intraoperative shoulder pain, postoperative pain after 2 h, and perioperative analgesic consumption (ketorolac) were significant better in group Magnesium than in group Bupivacaine. (P < 0.05). The onset of motor and sensory blocks was significant longer in group Magnesium than the other one. The incidence of PONV, pruritus and urinary retention was insignificant statistically between both groups. Conclusions: Magnesium sulfate if used intrathecally as an adjuvant to Bupivacaine would provide a better surgeon satisfaction and would improve the analgesic effect of spinal anesthesia used for gynecological laparoscopic surgery.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.32-36
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• 2006

Magnesium has been used as light and functional material, and its demand is increasing as a material for automobile engine and for mobile phone or notebook PC case. Fused salt electrolysis and thermal reduction are regarded as main methods for the extraction of magnesium, and choice for the method is firstly according to raw material. In this study, magnesium metal is obtained by an electrolysis of magnesium chloride. Two types of fused salt mixtures were used as electrolyte and electrolyzed at 7V with a graphite anode having the same depth, and their results were compared with each other. A mixed salt of $KCl/NaCl/MgCl_2$ was the more effective than $KCl/NaCl/CaCl_2/CaF_2/MgCl_2$ in current efficiency through the experiments at $760^{\circ}C$. Purity of the prepared magnesium metal was above 98%. Some basic data for scale-up of the magnesium electrolysis equipment, which would be necessary for a commercialization, could be obtained.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.220-224
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• 2003

Effect of the ingestion of porphyran extracted from Porphyra yezoensis on calcium, magnesium and potassium contents in serum and tissue was investigated using hyperlipidemic and hypercholesterolemic rats. The contents of calcium magnesium and potassium in serum of rats fed porphyran for four weeks were higher than those of the control group. The contents of calcium and potassium were decreased with increasing a porphyran level while magnesium content was increased. Liver calcium contents in an $1\%$ porphyran group were significantly (p<0.05) higher than those in the control group, and magnesium contents in a $10\%$ porphyran group were higher than those in the control group. Kidney calcium and magnesium contents in rats fed porphyran were significantly (p<0.05) high compared with the control group. However, potassium content in kidney was Increased as a porphyran level was increased in diet. Spleen calcium and potassium contents were significantly lower in the porphyran groups than those in the control group. Rats fed the $5\%$ porphyran diet had higher magnesium content in spleen than any other diets. The results showed that diets supplemented with several porphyran levels had variable effects on the contents of calcium, magnesium and potassium in serum and tissue of hyperlipidemic rats.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.2049-2054
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• 2013

Recently, magnesium hydroxide ($Mg(OH)_2$) has many applications in various field, due to its outstanding characteristics such as a nontoxic, noncorrosive and thermal stable properties. In this study, different shapes of flower and flake type magnesium hydroxide were synthesized by precipitation method at room temperature using $MgSO_4$, $MgCl_2$ and $Mg(NO_3)_2$ as magnesium sources, NaOH and $NH_3$ as alkaline sources. Influence of synthesis on the morphological characteristics, sizes and shapes of magnesium hydroxide particles, was investigated, such as different precursors and parameters. The shape of magnesium hydroxide depend on magnesium and alkali sources. Average size of flower particle had about $1{\mu}m$, and flake had about 20 ~ 50 nm. The synthesised magnesium hydroxide groups were characterized by XRD, FE-SEM, FT-IR, EDS, PSA and TG.