• Journal of Powder Materials
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• v.11 no.3
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• pp.224-232
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• 2004

Ni-diamond composite powders with nickel layer of round-top type on the surface of synthetic diamond (140/170 mesh) were prepared by the electroless plating method (EN) with semi-batch reactor. The effects of nickel concentration, feeding rates of reductant, temperature, reaction time and stirring speeds on the weight percentage and morphology of deposited Ni, mean particle size and specific surface area of the composite powders were investigated by Atomic Adsortion Spectrometer, SEM-EDX, PSA and BET. It was found that nucleated Ni-P islands, acted as catalytic sites for further deposition and grown into these relatively thick layers with nodule-type on the surface of diamond by a lateral growth mechanism. The weight percentage of Ni in the composite powder increased with reaction time, feeding rate of reductant and temperature, but decreased with stirring speed. The weight percentage of Ni in Ni-diamond composite powder was 55% at 150 min., 200 rpm and 7$0^{\circ}C$ .

• Journal of the Korean Society for Heat Treatment
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• v.34 no.2
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• pp.60-65
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• 2021

In this study, the effect of pressure type and foaming agent on the microstructural change of Al foam produced by powder compact processing was investigated. Better foaming characteristic is easily obtained from extrusion process with strong plastic deformation and preheating than that by uniaxial pressing with preheating. In current powder compact foaming process using TiH2/MgH2 mixture as a foaming agent, a temperature of 670℃ and addition of 30% MgH2 in TiH2 foaming agent was chosen as the most suitable foaming condition. The aluminum (Al) foams with maximum porosity of around 70%, relatively regular pore size and distribution were successfully produced by means of the powder metallurgy method and extrusion process.

• Journal of Powder Materials
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• v.23 no.4
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• pp.263-269
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• 2016

Graphene oxide (GO) powder processed by Hummer's method is mixed with p-type $Bi_2Te_3$ based thermoelectric materials by a high-energy ball milling process. The synthesized GO-dispersed p-type $Bi_2Te_3$ composite powder has a composition of $Bi_{0.5}Sb_{1.5}Te_3$ (BSbT), and the powder is consolidated into composites with different contents of GO powder by using the spark plasma sintering (SPS) process. It is found that the addition of GO powder significantly decreases the thermal conductivity of the pure BSbT material through active phonon scattering at the newly formed interfaces. In addition, the electrical properties of the GO/BSbT composites are degraded by the addition of GO powder except in the case of the 0.1 wt% GO/BSbT composite. It is found that defects on the surface of GO powder hinder the electrical transport properties. As a result, the maximum thermoelectric performance (ZT value of 0.91) is achieved from the 0.1% GO/BSbT composite at 398 K. These results indicate that introducing GO powder into thermoelectric materials is a promising method to achieve enhanced thermoelectric performance due to the reduction in thermal conductivity.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.649-657
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• 2011

In this study, the effects of kimchi powder on the quality properties of an emulsion type sausage made with irradiated pork meat were investigated. Raw ground pork ham was gamma-irradiated at 5 and 10 kGy, and the emulsion type sausage was then manufactured with the irradiated pork meat. The pH value was shown to increase by irradiation of raw material (p<0.05). Samples containing kimchi powder had a lower pH value than other treatments, but no significant differences were observed. In a sensory evaluation, the scores of all the criteria were decreased with an increased irradiation dose of raw material, but samples containing kimchi powder had a higher sensory score than other treatments in all irradiation doses of raw material. The TBARS values were increased by irradiation of raw material and the samples containing kimchi powder had the highest value (p<0.05). Odor substances analyzed by an electronic nose were increased with increased irradiation dose of raw material in all treatments, and samples containing kimchi powder showed a higher increase of odor substances than other treatments. Thus, this study demonstrated that kimchi powder was effective in eliminating the off-odor and flavor of sausages made with irradiated pork meat despite the increase of the TBARS value.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.75-76
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• 2006

New PM route via bulk mechanical alloying is developed to fabricate the solid solution semi-conductive materials with $Mg_2Si_{1-x}Ge_x$ and $Mg_2Si_{1-y}Sn_y$ for 0 < x, y < 1 and to investigate their thermoelectric materials. Since $Mg_2Si$ is n-type and both $Mg_2Ge$ and $Mg_2Sn$ are p-type, pn-transition takes place at the specified range of germanium content, x, and tin content, y. Through optimization of chemical composition, solid-solution type thermoelectric semi-conductive materials are designed both for n-and p-type materials.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.459-460
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• 2006

N-type $Bi_2Te_3-Sb_2Te_3$ solid solutions doped with 1$CdCl_2$ was prepared by melt spinning, crushing and vacuum sintering processes. Microstructure, bending strength and thermoelectric property were investigated as a function of the doping quantity from 0.03wt.% to 0.10wt.% and sintering temperature from $400^{\circ}C$ to $500^{\circ}C$, and finally compared with those of conventionally fabricated alloys. The alloy showed a good structural homogeneity as well as bending strength of $3.88Kgf/mm^2$. The highest thermoelectric figure of merit was obtained by doping 0.03wt.% and sintering at $500^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.785-789
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• 2014

An experiment was conducted to investigate the effects of feeding by different feed types (powder, crumble and pellet) of two different feed formulations with simple dried (D) or extruded (E) conditions on growth and body composition of juvenile sea cucumber Apostichopus japonicus. Triplicate groups of sea cucumber averaging $1.2{\pm}0.05g$ were fed each of the D1, D2, EP1 or EP2 diets for 12 weeks. Survival of sea cucumber fed D2-crumble was higher than that fed EP2-crumble diet (P<0.05). Weight gain of sea cucumber fed EP1-powder was higher than that fed EP1-crumble and EP2-crumble diets (P<0.05). These findings indicated that simple dried feed could use independently feed type for sea cucumber culture and powder type of extruded feed is also good for sea cucumber culture.

• Journal of Powder Materials
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• v.18 no.5
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• pp.423-429
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• 2011

Thermoelectric-thick films were fabricated by using a screen printing process of n and p-type bismuth-telluride-based pastes. The screen-printed thick films have approximately 30 ${\mu}m$ in thickness and show rough surfaces yielding an empty gap between an electrode and the thick film. The gap might result in an increase of an electrical resistivity of the fabricated thick-film-type thermoelectric module. In this study, we suggest a conductive metal coating onto the surfaces of the screen-printed paste in order to reduce the contact resistance in the module. As a result, the electrical resistivity of the thermoelectric module having a gold coating layer was significantly reduced up to 30% compared to that of a module without any metal coating. This result indicates that an introduction of conductive metal layers is effective to decrease the contact resistivity of a thick-film-typed thermoelectric module processed by screen printing.

• Journal of Life Science
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• v.25 no.8
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• pp.896-902
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• 2015

This study was conducted to evaluate the substitution effect of red beet powder on sodium nitrite in emulsion-type pork sausages, and to investigate the effect of the addition of red beet powder on the physicochemical characteristics of emulsion-type pork sausages at 10℃ for 6 weeks. The treatments were divided into five groups: Control (sodium nitrite 0.01%), T1 (sodium nitrite 0.005% + red beet powder 0.5%), T2 (sodium nitrite 0.005% + red beet powder 0.25%), T3 (red beet powder 0.5%), and T4 (red beet powder 0.25%). In the CIE^*I didn’t delete this asterisk (*) because it might be a marker for something you wish to add later, but please note that if there is no significance for the asterisk, it should be removed as a typographical error. color of emulsion-type pork sausages, the lightness value of the control was significantly higher than for the other groups (p＜0.05). The redness value was higher in T1, whereas the yellowness value was higher in the T3 and T4 groups compared with the others (p＜0.05). The pH values of emulsion-type pork sausages were significantly decreased in the T3 and T4 groups by the addition of red beet powder (p＜0.05). However, the DPPH radical-scavenging activity was higher in the T1 and T3 groups than in the others (p＜0.05). The residual nitrite ion was the highest in the control group (p＜0.05). Therefore, it is determined that red beet powder can substitute for nitrite as a natural colorant, and it has a slightly antioxidant effect in emulsion-type pork sausages.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.582.2-582.2
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• 2006