• Korean Journal of Medicinal Crop Science
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• v.13 no.5
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• pp.227-232
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• 2005

The antioxidant effect of methanol extract (ME) and water extract (WE) from Clematis trichotoma was evaluated as primary study to scavenge stable 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), inhibited iron-induce lipid peroxidation in linoleic acid emulsion, peroxidation of liposome induced by $Fe^{3+}/H_2O_2/ascorbie$ acid, and on $Fe^{2+}/H_2O_2$ induced the mitochondrial lipid peroxidation. In secondary study, five flavonoids as luteolin (1), quercetin (2), apigenin (3), hirsutrin (4), kaempferol-3-O-glucoside were isolated (5). Among them, compounds 1 and 2 showed good activities in all the model systems. Compound 3 exhibited moderate antioxidant activities in both radical scavenging and these lipid peroxidation systems tested. Compound 4 showed significant inhibitions in liposome peroxidation and compound 5 displayed weak inhibition in all four tested systems. All the results presented herein indicate that products of C. trichotoma maybe useful in inhibiting membrane lipid peroxidation and preventing free radical-linked diseases.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2368-2373
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• 1994

The advancement of the mechanical properties of metal materials caused by a recent high technology contributes to the stability and productivity of mechanical structures. However, the advanced mechanical properties depends on the conditions of crystal boundaries and the improvement of the texture. Although the tensile strength and a hardness of a steel would be increased by the adding B, it seems to be a marked decreases of the toughness which caused in the weaken workability. This study is concerned with a characteristics of the B compound which will be mixed with $H_3BO_3$ and the metallic magnesium. What affected in the mechanical property and texture is checked by the strength and the texture test. As a result, it is shown that the improvement of the mechanical property and the texture homogeneity. In addition, it seems that a molten metal which is added by the B compound is deoxized and cleansed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.652-660
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• 2004

The cis-hex-3-ene-1,5-diynyl-bridged diiron compound 3, [(η$^{5}$ - $C_{5}$ M $e_{5}$ ) Fe(dppe)］$_2$($\mu$-C≡C-CH=CH-C≡C), have been prepared and characterized by cyclic voltammetry(CV), and electronic spectroscopy (UV-VIS and near-IR, NMR). From the results, compound 3 show two well resolved, single-electron, reversible oxidation waves by CV, and comproportionation constant(Kc) calculated from the CV data for compound 3. The Mixed-valence (MV) radical cation 3$^{+}$ show strong absorptions in the near IR, 1586 nm, and this band is more readily assigned as MV $\pi$-$\pi$ band of delocalized complex (Robin-Day Mixed-valence Class III), and the $H_{ab}$ , effective coupling parameter are most consistent with electronic delocalization.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.1
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• pp.2-9
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• 2003

The aluminum alloy which is light and has excellent thermal conductivity and iron base alloy that is remarkable heat-resistece and wear resistence properties were bonded together. The bond was created between a stationary and a rotating member by using the frictional heat generated between them while subjected to high normal forces on the interface of Al alloy and iron base alloy. The microstructure of the bonded interface of friction welding and the strength in the bonded interface formed under various bonding conditions were examined through TEM, SEM with EDX and triple bending test. In interface of bonding materials formed after various heat treatment, bonding strength was substantially different, resulting from formation of intermetallic compound or softening during annealing.

• Korean Journal of Materials Research
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• v.33 no.9
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• pp.353-359
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• 2023

This study investigated the growth behavior and characteristics of compounds formed at the interface between a liquid Al-Si-Cu alloy and solid cast iron. Through microstructural analyses, it was observed that various AlFe and AlFeSi phases are formed at the interface, and the relative proportion of each phase changes when small amounts of strontium are added to the Al alloy. The results of the microstructural analysis indicate that the primary phases of the interfacial compounds in the Al-Si-Cu base alloy are Al₈Fe₂Si and Al_4.5FeSi. However, in the Sr-added alloys, significant amounts of binary AlFe intermetallic compounds such as Al₅Fe₂ and Al₁₃Fe₄ formed, in addition to the AlFeSi phases. The inclusion of Sr has a slight diminishing effect on the rate at which the interfacial compounds layer thickens during the time the liquid Al alloy is in contact with the cast iron. The study also discusses the nano-indentation hardness and micro-hardness of the interfacial phases.

• Journal of Korea Foundry Society
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• v.2 no.3
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• pp.2-15
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• 1982

In this study, the influenced of graphite shape on the boriding of cast iron and boride structure was investigated. Gray cast iron, ferritic and pearlitic ductile cast iron were borided at 750,850,900 and $950^{\circ}C$ for 1,3 and 5 hours by powder pack method with the mixture of $B_4C_9\;Na_2B_4O_7$, $KBF_4$ and Shc. The boride layer was consisted of FeB(little), $Fe_2B$ (main) and graphite. Some possibility of the existence of unknown Fe-B-C compound in the boride layer was suggested. And precipitates in the diffusion zone was $Fe_3(B,C)$. The concentration of Si and precipitation of $Fe_3(B,C)$ in the ${\alpha}$ layer raised the hardness of this Zone. The depth and hardness of boride layer increased with the increase of treating temperature and tim. But high temperature (over $950^{\circ}C)$ caused pore at graphite position and long treating time (5hrs) sometimes caused formation of graphite layer beneath the boride layer. So, for the practical application of borided cast iron, treating in short time and at low temperature was recommended. And for ductile cast iron, ferritizing or pearlitizing heat treatment was seemmed to be possible at the same time with boriding. The graphite in the boride layer was deeply concerned with the qualitx and characteristics of the boride layer. And it greatly influenced on the shape of the boride phase, structure of the boride layer. Generally speaking, the existance of graphite restrained the growth of the boride phase. But the boundary between the gsaphite and the matrix acted as the shortcut of boron diffusion. So, for gray cast iron, the graphite layed length-wise led the formation of boride layer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.73-74
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• 2022

The corrosion inhibitive effect of a new hydrazone-based heterocyclic compound for steel in simulated concrete pore solution with 3.5 wt.% sodium chloride was investigated by experimental and computational techniques. Electrochemical studies, up to 30 days of immersion, and surface analysis (X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscope (SEM)) were performed to assess the corrosion protection abilities of investigated compound for steel rebar. Results showed that adding the organic compound to the chloride contaminated concrete pore solution decreased the corrosion rate of the steel rebar thanks to the effective adsorption of inhibitor molecules. After 30 days of immersion of steel rebar in inhibited chloride contaminated synthetic concrete pore solution, the inhibition efficiency exceeded 80% at low concentration of 1 mmol/L. Computational studies by Density Functional based Tight Binding (DFTB) method revealed the formation of covalent bonds between the hydrazone molecule and the iron surface.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.631-640
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• 1999

The present study investigated the stimulatory effects of iron (or ascorbate) on cyclosporine-induced kidney mitochondrial damage. Damaging effect of $50\;{\mu}M$ cyclosporine plus $20\;{\mu}M\;Fe^{2+}$ on mitochondrial lipids and proteins of rat kidney and hyaluronic acid was greater than the summation of oxidizing action of each compound alone, except sulfhydryl oxidation. Cyclosporine and $100\;{\mu}M$ ascorbate showed an enhanced damaging effect on lipids but not on proteins. The peroxidative action of cyclosporine on lipids was enhanced with increasing concentrations of $Fe^{2+}.$ Ferric ion $(20\;{\mu}M)$ also interacted with cyclosporine to stimulate lipid peroxidation. Damaging action of cyclosporine on mitochondrial lipids was enhanced by ascorbate $(100\;{\mu}M\;and\;1\;mM)$. Iron chelators, DTPA and EDTA, attenuated carbonyl formation induced by cyclosporine plus ascorbate. Cyclosporine $(100\;{\mu}M)$ and $50\;{\mu}M\;Fe^{2+}$ $(or\;100\;{\mu}M\;ascorbate)$ synergistically stimulated degradation of $2-{\alpha}$ deoxyribose. Cyclosporine $(1\;to\;100\;{\mu}M)$ reduced ferric ion in a dose dependent manner, which is much less than ascorbate action. Addition of $Fe^{2+}$ caused a change in absorbance spectrum of cyclosporine in $230{\sim}350$ nm of wavelengths. The results show that cyclosporine plus iron (or ascorbate) exerts an enhanced damaging effect on kidney mitochondria. Iron and ascorbate appear to promote the nephrotoxicity induced by cyclosporine.

• Environmental and Resource Economics Review
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• v.19 no.2
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• pp.341-360
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• 2010

The goal of this study is to forecast the scales of seaborne trade of iron ore and coal. It is assumed that the seaborne trade of iron ore is the function of two independent variables(crude steel production, world GDP) and the seaborne trade of coal is the function of two independent variables(crude steel production, world electricity generation). The result shows that the regressions of two functions are statistically significant respectively. As the results of forecasting, the seaborne trade of iron ore in 2010 may be 892 million tons which is increased 5.1% compare to the level of 2009. Also the seaborne trade of coal in 2010 may be 827 million tons which is increased 6.1% compare to the level of 2009. In terms of the compound annual growth rate, it is forecasted that the iron ore may show 4.7% of increasing rate from 2009 to 2015 and the seaborne trade of coal may be increased 6.1% annually for the same period.

• Journal of Nutrition and Health
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• v.5 no.2
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• pp.91-103
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• 1972

Zinc is one of the essential trace elements in the living organism for growth and health. The first identified metalloenzyme, carbonic anhydrase, is a zinc compound and several others have been described since. Among zinc deficiency syndromes in animals porcine parakeratosis has been successfully treated with zinc supplements, and in man a syndrome of anemia, hypogonadism, hepatosplenomegaly, and dwarfism, prevalent in parts of Iran and Egypt, has been ascribed to lack of zinc in the diet. Dietary zinc excess in the rat is manifested by a hypochromic, microcytic anemia, poor growth, reduction in liver catalase and cytochrome oxidase. The present study is an attempt to delineate the changes of tissue contents of trace elements, especially of iron, copper and zinc in liver and kidneys of the rats. Weanling albino rats, weighing 60 to 80gm. were used in this experiments. The rats were housed in cages with aluminum floors and received feed and distilled water ad libitum. Animals were divided into three groups, control, low zinc diet and high zinc diet groups. The high zinc diet group was subdivided into 0.5% Zn and 0.7%Zn groups. The supplementary copper or iron was added to the high dietary zinc groups. The animals were sacrificed and the tissues were washed several times with deionized water. The wet digested samples were analyzed by Hitachi Model 207 atomic absorption spectro-photometer for the determination of iron, copper and zinc in the liver and kidney. Hemoglobin level in the blood was measured by cyanmethemoglobin method. The results of this study are as follows: 1) All rats fed high zinc diets and low zinc diets gained less weight than control. Weight gain was not improved by the supplementary copper or iron and both. 2) Hemoglobin concentration was decreased significantly in the rats fed high zinc diets and less in the low zinc diet. Supplementary copper and iron to the higher zinc diet appeared to give some improvement of anemia. 3) The iron contents of the liver and kidneys were significantly decreased in the high zinc groups and the reduction was more significantly in the rats receiving higher zinc diet (0.7%). The supplementary copper caused a further depression of liver iron. On the other hand, the iron, added to the high zinc diet lessoned the severity of the decrease in liver iron and caused kidney iron to be maintained almost at the level found in the rats fed by zinc and supplementary copper diet. 4) High zinc diets did not change copper content of the liver and kidney. Supplementary copper elevated the concentration in the liver and kidney and added iron had no effect on the accumulation of copper in the liver and kidneys. 5) The high zinc diets caused marked increases of zinc content in the liver and kidney. Supplementary iron to the high zinc diet caused increases of zinc contents of liver and kidneys.