• Journal of the East Asian Society of Dietary Life
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• v.10 no.6
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• pp.495-506
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• 2000

The purpose of this study was to assess the nutritional status of iron and magnesium and the effect of von supplementation during 8 weeks(from 20 to 28 weeks of gestation) on serum iron and magnesium status of 31 pregnant women in Kyunsin area. The age, weight, and height of the subjects before pregnancy were investigated by questionnaires. At 20 and 28 weeks of gestation, data for food and nutrient intake were obtained by questionnaires and serum sample was obtained. According to the frequency of iron supplementation, subjects were divided into two groups(4$\geq$/wk) The mean iron supplementation of 5 $\geq$/wk group(63.mg/day) was significantly higher than 4$_2$ intakes were much less than the Korean RDA. Especially, calcium, iron and magnesium intakes showed half the levels compared with Korean RDA. At 28 weeks of gestation the serum total protein(p<0.001), albumin(p<0.01) and globulin(p<0.001) were significantly decreased. Total iron binding capacity(TIBC) was significantly increased(P<0.001), but serum ferritin(p<0.01) and magnesium(p<0.01) concentrations were significantly decreased. However, even 28 weeks of gestation 5$\geq$/wk group showed higher serum iron and ferritin concentration and lower TIBC than 4$\geq$/wk group. Therefore, iron supplementation should be conducted with concerning the mineral balance like magnesium.

• YAKHAK HOEJI
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• v.27 no.2
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• pp.139-148
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• 1983

The neutralizing capacities of the antacids, which are frequently used in Korean market, were evaluated in vitro by the methods of Resset and Rice, Fordtran and Collyns, and modified Beekman, respectively. The antacids used in the study are two kinds, the one is preparations from Seoul National University Hospital and the other is products from pharmaceutical companies, and their components are aluminum phosphate, aluminum hydroxide, magnesium aluminum hydroxide, magnesium hydroxide, basic aluminum sucrose sulfate and $2MgO{\times}Al_{2}O_{3}{\times}SiO_{3}$, etc. The hospital preparations, DMC and MAC powders, showed most powerful and sustained neutralizing capacities, i.e. they maintained the pH range from 5 to 8 for 60min, Whereas pharmaceutical products, aluminum hydroxide gel containing magnesium hydroxide and magnesium aluminum hydroxide gel exhibited a moderate capacities, i.e pH ranged from 3 to 6, and aluminum phosphate, $2MgO{\times}Al_{2}O_{3}{\times}SiO_{2}$ and basic aluminum sucrose sulfate displayed a weak activity, pH ranged from 2 to 3. When the therapeutic doses of aluminum hydroxide gel containing magnesium hydroxide and magnesium aluminum hydroxide gel were divided into 2 doses and each dose was used at the interval of 30min., the divided doses kept more prolonged higher pH than the single therapeutic dose. Milliequivalents of neutralizing capacities of each antacid were measured by the method of Fordtran and Collyns. The milliequivalents per 1ml of aluminum hydroxide gel, aluminum hydroxide gel containing magnesium hydroxide, magnesium aluminum hydroxide gel and aluminum phosphate were 2.87, 2.86, 2.57, and 0.67, respectively. The milliequivalents per 100mg of preparations, i.e. MAC powder, dried aluminum hydroxidgel, DMC powder, 2MgO, $Al_{2}O_{3}$. $SiO_{2}$, magnesium aluminum hydroxide and basic aluminum sucrose sulfate were 1.91, 1.68 1.63, 1.45, 1.44, and 0.44, respectively.

• Journal of the Korean Society for Heat Treatment
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• v.33 no.3
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• pp.129-134
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• 2020

Due to excellent properties such as high specific strength and low density, application of magnesium alloys have been rapidly increased. However, magnesium alloy has a serious problem that is easily oxidized when exposed to high-temperature. For this reason, magnesium alloys have been generally used for SF6 gas such as protective cover gas in casting and melting, but it has been reported that this gas has a serious influence on global warming. Therefore, many researchers have been studied to improve the oxidation resistance of magnesium alloy. It was reported that addition of Be, Ca and CaO in magnesium alloy can improve the oxidation properties. In this study, the possibility of improving the oxidation resistance by adding CaO extracted from oyster shells was investigated. Oyster shells were completely decomposed into CaO and CO₂ by annealing. With the addition of CaO, a coexistence region of MgO + CaO was formed in the oxide layer and its thickness was also reduced.

• Journal of Powder Materials
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• v.18 no.4
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• pp.359-364
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• 2011

Zr-Ti alloy powders were successfully synthesized by magnesium thermal reduction of metal chlorides. The evaporated and mixed gasses of $ZrCl_4+TiCl_4$ were injected to liquid magnesium and the chloride components were reduced by magnesium leading to the formation of $MgCl_2$. The released Zr and Ti atoms were then condensed to particle forms inside the mixture of liquid magnesium and magnesium chloride, which could be dissolved fully in post process by 1~5% HCl solution at room temperature. By the fraction-control of individually injected $ZrCl_4$ and $TiCl_4$ gasses, the final compositions of produced alloy powders were changed in the ranges of Zr-0 wt.%~20 wt.%Ti and their purity and particle size were about 99.4% and the level of several micrometers, respectively.

• Journal of Nutrition and Health
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• v.28 no.5
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• pp.442-450
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• 1995

This study determined plasma glucose, free fatty acid(ffa), epinephrine, norepinephrine, creatine the phosphokinase(CPK), calcium (Ca), magnesium(Mg) and hydroxyproline, Ca and Mg in the heart muscle. Thirty six male Sprague Dawley rats average weighing 110g divided into two diet group : normal Mg group(0.05% Mg), Marginal Mg group(0.005% Mg). After the rats were on experimental diets for 2 weeks, rats for each group were randomly assigned to stress and no stress group and 30 minutes IMMB stress was administered to stress group every day for two weeks. The following were found : 1) Rats fed normal magnesium diet showed decreased plasma glucose and non signficant change in norepinephrine and CPK with IMMB stress, while magnesium deficient rats showed elevated plasma glucose, norepinephrine and CPK with stress. 2) Myocardial hydroxyproline and plasma epinephrine were not significantly different among groups. 3) In the rats fed adequate magnesium, stress increased plasma magnesium while rats on marginal magnesium diet did not show significant change with stress. 4) Plasma and myocardial calcium were increased in rats fed marginal Mg diet, but did not show any significant difference with stress.

• Advances in materials Research
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• v.1 no.3
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• pp.169-182
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• 2012

In this paper the intrinsic influence of micron-sized nickel particle reinforcements on microstructure, micro-hardness tensile properties and tensile fracture behavior of nano-alumina particle reinforced magnesium alloy AZ31 composite is presented and discussed. The unreinforced magnesium alloy (AZ31) and the reinforced nanocomposite counterpart (AZ31/1.5 vol.% $Al_2O_3$/1.5 vol.% Ni] were manufactured by solidification processing followed by hot extrusion. The elastic modulus and yield strength of the nickel particle-reinforced magnesium alloy nano-composite was higher than both the unreinforced magnesium alloy and the unreinforced magnesium alloy nanocomposite (AZ31/1.5 vol.% $Al_2O_3$). The ultimate tensile strength of the nickel particle reinforced composite was noticeably lower than both the unreinforced nano-composite and the monolithic alloy (AZ31). The ductility, quantified by elongation-to-failure, of the reinforced nanocomposite was noticeably higher than both the unreinforced nano-composite and the monolithic alloy. Tensile fracture behavior of this novel material was essentially normal to the far-field stress axis and revealed microscopic features reminiscent of the occurrence of locally ductile failure mechanisms at the fine microscopic level.

• Journal of Korea Foundry Society
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• v.34 no.1
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• pp.14-21
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• 2014

Magnesium and its alloys are being applied to various kinds of industrial fields, especially their use on automotive parts and electronic part. These parts are manufactured mainly through diecasting process and magnesium ingots are used as raw materials. In the case that ingot quality is not secured, massive casting defects can occur and some manufactures can be damaged by the defects. This study is to evaluate ingots' cleanliness of magnesium alloys. It includes composition analysis by spectrometer, measurement of inclusion contents by SEM, brightness test on fractured surface and etc. Especially, the brightness test is a very easy and quick evaluation method. The brightness becomes low when the amount of oxides or inclusions on the surface increases. The brightness test data have been compared with those obtained from other methods for measuring the mount of impurities, which showed good relationship between the brightness and the others. Thus, the brightness test could be a promising method to measure the cleanliness of magnesium alloys.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.1
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• pp.33-41
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• 1988

In a study about minerals cycling in grassland agro-ecosystem, investigation on relations among two minerals, potassium(K) and magnesium(Mg), and nitrogen(N) was performed. Four kinds of diets different in K and N levels were fed to four goats with a Latin-square method and $2{\times}2$ factorial design. As the basal diet, press cake silage prepared from Italian ryegrass was used because of its uniformity and comparatively low mineral concentrations. Supplementation of K and N were made using potassium bicarbonate and urea. In the experiment, it was clearly shown that high K concentration in the forage crops is the main reason of the low utilization of Mg in ruminant animals. However, high nitrogen intake resulted in the increase of magnesium retention, urinary potassium excretion, water intake and volume of urine and in the decreases of potassium intake minus urinary potassium excretion. The results of high nitrogen intake seemed to be produced in the following order;increase of urine, increase of water intake, increase of urinary potassium excretion, and decrease of intake minus urinary potassium excretion. The amount of potassium intake minus urinary potassium excretion had significantly close relationships with magnesium utilization and serum magnesium concentration. As a conclusion, higher nitrogen intake by ruminants seemed to be preferable for magnesium utilization through increased water intake and urinary potassium excretion, if the sufficient drinking water could be supplied to ruminants.

• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.232-240
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• 2006

Magnesium alloys are expected to be widely used fur the parts of structural and electronic appliances due to their lightweight and EMI shielding characteristics. While the die casting has been mainly used to manufacture the parts from the magnesium alloys, the press forming is considered as an alternative to the die casting for saving the manufacturing cost and improving the structural strength of the magnesium alloy parts. However, the magnesium alloy has low formability at room temperature and therefore, in many cases, forming at elevated temperatures is necessary to obtain the required material flow without failure. In the present study, square cup deep drawing tests using the magnesium alloy AZ31 sheet were experimentally conducted at various elevated temperatures as well as room temperature, and the corresponding finite-element simulations, which calculated the damage evolution based on the Oyane's criterion, were conducted using the stress-strain relations from the tensile tests at various temperatures. The formability predictability by the finite-element analysis was investigated by comparing the predicted damage distributions over the deformed AZ31 sheet at elevated temperatures with the corresponding experimental deformations with failures.

• Journal of the Korean Society for Heat Treatment
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• v.33 no.2
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• pp.49-56
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• 2020

Magnesium alloy is a metal with high specific strength and light weight, and is attracting attention as a next generation metal for environmentally friendly automobiles and transportation equipment. However, magnesium alloys have a problem of degrading formability due to the basal texture developed during processing, and their application is limited. Although active researches on the control of textures have been conducted in order to minimize this problem, there is a lack of research on the formation of microstructures and textures according to elemental differences. In this study, AZ61 and AZ80 magnesium alloys were selected to investigate the effects of aluminum addition on the microstructure development of magnesium alloys. This research has proven that the increase of the rolling rate results in the decrease of the average grain size of the two alloys, the increase of the hardness, and the increase of the fraction of twins. As shown on this research below, the basal texture developed strongly as the rolling ratio increased. On the other hand, this research also has proven that the two alloys exhibited different texture strength and distribution tendencies, which could be due to the effects of aluminum addition on work hardening, grain size, and twin behavior.