• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.5
• /
• pp.521-526
• /
• 2007

The effects of red ginseng powder on hepatotoxicity in $benzo(\alpha)pyrene\;[B(\alpha)P]$-treated mice were investigated. Male ICR mice were pretreated with red ginseng powder (50 or 100 mg/kg/day, for 5 days, intraperitoneally) before treatment with $B(\alpha)P$ (0.5 mg/kg, i.p, single dose). The ability of red ginseng powder to protect against oxidative damage to the mouse liver was examined by determining the level of lipid peroxide, glutathione, and the antioxidant enzyme activities. The glutathione content depleted by $B(\alpha)P$ were significantly increased by red ginseng powder, but elevation of lipid peroxide content induced by $B(\alpha)P$ was decreased by red ginseng powder. The increased activities of superoxide dismutase, catalase and glutathione peroxidase after $B(\alpha)P$-treatment were decreased by the treatment of red ginseng Powder; however, glutathione S-transferase activity depleted by $B(\alpha)P$ were significantly increased. These results suggest that red ginseng powder can protect against $B(\alpha)P$ intoxification through its antioxidant properties.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2001.11a
• /
• pp.8-9
• /
• 2001

• Journal of Powder Materials
• /
• v.20 no.3
• /
• pp.221-227
• /
• 2013

$TiB_2$-reinforced iron matrix composite (Fe-$TiB_2$) powder was in-situ fabricated from titanium hydride ($TiH_2$) and iron boride (FeB) powders by the mechanical activation and a subsequent reaction. Phase formation of the composite powder was identified by X-ray diffraction (XRD). The morphology and phase composition were observed and measured by field emission-scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The results showed that $TiB_2$ particles formed in nanoscale were uniformly distributed in Fe matrix. $Fe_2B$ phase existed due to an incomplete reaction of Ti and FeB. Effect of milling process and synthesis temperature on the formation of composite were discussed.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 1997.10a
• /
• pp.32-33
• /
• 1997

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2002.04b
• /
• pp.26-27
• /
• 2002

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2002.04b
• /
• pp.42-43
• /
• 2002

• Korean Journal of Materials Research
• /
• v.15 no.6
• /
• pp.399-407
• /
• 2005

The effect of IN738 additive powder on microstructure and mechanical properties of the wide-gap region brazed with BNi-3 filler metal powder was investigated. The wide-gap brazing was conducted in a vacuum of $2\times10^{-5}torr\;at\;1200^{\circ}C$ with various powder mixing ratios of additive to filler powders. The microstructures of the wide-gap brazed region were analyzed by SEM and AES. The region brazed with only BNi-3 filler metal powder had a microstructure consisted of proeutectic, binary eutectic and ternary eutectic structure, while that brazed with a mixture of IN738 additive powder and BNi-3 filler metal powder had a microstructure consisted of IN738 additive powder, binary eutectic of $Ni_3B-Ni$ solid solution and (Cr, W)B. The fracture strength of the wide-gap brazed region was about 680 MPa regardless of the additive powder mixing ratios. Cracks were initiated at the (Cr, W)B and binary eutectic of $Ni_3B-Ni$ solid solution, and propagated through them in the wide-gap brazed region, which lowered the fracture strength of the region.

• Journal of Powder Materials
• /
• v.20 no.5
• /
• pp.359-365
• /
• 2013

In this study, we fabricated $Nd_2Fe_{14}B$ hard magnetic powders with various sizes via spray drying combined with reduction-diffusion process. Spray drying is widely used to produce nearly spherical particles that are relatively homogeneous. Thus, the precursor particles were prepared by spray drying using the aqueous solution containing Nd salts, Fe salts and boric acid with the target stoichiometric composition of $Nd_2Fe_{14}B$. The mean particle sizes of the spray-dried powders are in the range from one to seven micrometer, which are adjusted by controlling the concentrations of precursor solutions. After debinding the as-prepared precursor particles, ball milling was also conducted to control the particle sizes of Nd-Fe-B oxide powders. The resulting particles with different sizes were subjected to subsequent treatments including hydrogen reduction, Ca reduction and washing for CaO removal. The size effect of Nd-Fe-B oxide particles on the formation of $Nd_2Fe_{14}B$ phase and magnetic properties was investigated.

• Progress in Superconductivity and Cryogenics
• /
• v.18 no.4
• /
• pp.9-14
• /
• 2016

The effect of the size and shape of magnesium(Mg) powder on the formation of $MgB_2$ and the critical current density($J_{c,}$) of $MgB_2$ bulk was studied. As a precursor for the formation of $MgB_2$, Mg and $MgB_4$ powder, which was synthesized through the reaction of boron (B) with Mg powders, was used. $MgB_4$ was mixed with Mg powders of various sizes, pressed into pellets and heat-treated at $650^{\circ}C-750^{\circ}C$ in flowing argon gas. The XRD analysis of the heat-treated $MgB_2$ samples showed that the volume fraction of $MgB_2$ was the highest as 92.74 % when spherical Mg powder with an average size of $25.7{\mu}m$ was used, whereas the volume fraction was the lowest as 79.64 % when plate-like Mg powder with a size of $34.1{\mu}m$ was used. The superconducting transition temperature ($T_c$) of $MgB_2$ was not sensitive to the characteristics of the Mg powders used. All of the prepared $MgB_2$ samples showed a high $T_c$ of 38.3 K and a small superconducting transition width of 0.2 K-0.5 K. $J_c$ (5 K and 1 T) of $MgB_2$ was the highest as $3.93{\times}10^4A/cm^2$ when spherical Mg powder with a size of $25.7{\mu}m$ was used, whereas $J_c$ was the lowest as $2.18{\times}10^4A/cm^2$when plate-like Mg powder with a size of $34.1{\mu}m$ was used. The relationship between the $J_c$ of $MgB_2$ and the characteristics of the Mg powders used was explained in terms of the volume fraction of $MgB_2$ and the apparent density of the $MgB_2$ pellets.

• Journal of Powder Materials
• /
• v.14 no.5
• /
• pp.292-297
• /
• 2007

The present study was focused on the synthesis of a $TiB_2$ dispersed copper matrix composite material by the combination of the mechanical milling and plasma activated sintering processes. The $Cu/TiB_2$ mixed powder was prepared by the combination of the mechanical milling and reduction processes using the copper oxide and titanium diboride powder as the raw material. The synthesized $Cu/TiB_2$ mixed powder was sintered by the plasma activated sintering process. The hardness and electric conductivity of the sintered bodies were measured using micro vickers hardness and four probe method, respectively. The relative density of $Cu/TiB_2$ composite material sintered at $800^{\circ}C$ showed about 98% of theoretical density. The $Cu-1vol%TiB_2$ composite material has a hardness of about 130Hv and an electric conductivity of about 85% IACS. The hardness and electric conductivity of $Cu-3vol%TiB_2$ composite material were about 140 Hv and about 45% IACS, respectively.