• Journal of Powder Materials
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• v.8 no.2
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• pp.110-116
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• 2001

Abstract To investigate the effect of mechanical alloying process to thermoelectric properties of PbTe sintered body, Pb-Te mixed powder with Pb : Te : 1 : 1 composition was mechanically alloyed using tumbler-ball mill. Thermoelectric properties of the sintered body were evaluated by measuring of the Seebeck coefficient and specific electric resistivity from the room temperature to 50$0^{\circ}C$. Sintered body of only mechanically alloyed PbTe powder showed p-type behavior at the room temperature, and occurred type transition from p-type to n-type at about 30$0^{\circ}C$. PbTe sintered body which was fabricated using heat treated powder in $H_2$ atmosphere after mechanical alloying showed stable n-type behavior under 50$0^{\circ}C$. N-type PbTe sintered body fabricated by mechanical alloying process had 4 times higher power factor than that fabricated by the melt-crushing process. Application of a mechanical alloying process to fabricate of n-type PbTe thermoelectric material seemed to be useful to increase the power factor of PbTe sintered body.

• Journal of the Korean Home Economics Association
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• v.48 no.2
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• pp.113-120
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• 2010

Quality characteristics effects of adding four different amounts (0%, 1%, 2%, 3%) of Ulleung-Maesil (Prunus mume fruit) powder cookie doughs were examined. pH, water content & bulk density of dough, spread factor, color value, hardness and consumer acceptability of maesil cookies were measured. The pH and water content of freezedried Ulleung-Maesil powder were 2.01 and 6.26%, respectively, while the L, a, b values were 76.14, -1.66 and 28.65, respectively. Although bulk density of the 3% powder group of cookie dough was the highest, its pH value was the lowest compared to the other groups (p < 0.05). Spread factor of the 3% group showed the lowest value among all groups (p < 0.05). Hardness of the control group (i.e, 0%) was significantly higher than the 1%, 2%, 3% groups (p < 0.05), which showed no significant difference among themselves. The ${\Delta}E$ value of cookies increased significantly with increasing Maesil powder content (p < 0.05). The consumer acceptability scores for control and 1% Maesil cookie groups ranked significantly higher than the 2% and 3% groups in overall acceptability, taste, flavor and texture (p < 0.05). In conclusion, our study suggests that small amounts of Ulleung-maesil can add positive attributes to cookies.

• Journal of Powder Materials
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• v.17 no.6
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• pp.482-488
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• 2010

In this study, $FeSi_2$ as high temperature performance capable thermoelectric materials was manufactured by powder metallurgy.The as-casted Fe-Si alloy was annealed for homogenization below $1200^{\circ}C$ for 3 h. Due to its high brittleness, the cast alloy transformed to fine powders by ball-milling, followed by subsequent compaction (hydraulic pressure; 2 GPa) and sintering ($1200^{\circ}C$, 12 h). In order to precipitate ${\beta}-FeSi_2$, heat treatment was performed at $850^{\circ}C$ with varying dwell time (7, 15 and 55 h). As a result of this experiment thermoelectric phase ${\beta}-FeSi_2$ was quickly transformed by powder metallurgical process. There was not much change in powder factor between 7h and 55h specimens.

• The Korean Journal of Food And Nutrition
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• v.28 no.5
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• pp.802-812
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• 2015

This study examined the quality characteristics of cookies comprised of various amounts of barley-sprout powder by analyzing the physico-chemical characteristics of the cookies and investigating a sensory evaluation. For the study, the cookies were cooked with the following levels of barley-sprout powder: 0%, 3%, 6%, 9%, and 12%. The results show that the moisture content of the cookies was increased in accordance with the level of barley-sprout powder and this result is the same as the spreadability factor of the cookies (p<0.001). Also, the pH and brix values of the samples decreased in accordance with the level of barley-sprout powder (p<0.001). Regarding hunter's colors, the values of L (lightness), a (redness), and b (yellowness) are significantly decreased, increasing the quantity of barley-sprout powder (p<0.001). For the textural characteristics, the results show that the hardness of the cookies decreased in accordance with the addition of the barley-sprout powder; furthermore, the results indicate a tendency whereby the DPPH-radical-scavenging activity and the total polyphenol content of the cookies were increased, thereby increasing the quantity of the barley-sprout powder (p<0.001). For the sensory evaluation, the cookies that were made with 6 % barley-sprout powder received the highest scores in terms of appearance, taste, and overall preference (p<0.05, p<0.001). This study suggests that barley-sprout powder is an excellent ingredient for improving the acceptability and functionality of cookies, and that, in relation to the flour quantity the ideal proportion of barley-sprout powder is 6%.

• Journal of Powder Materials
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• v.11 no.3
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• pp.217-223
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• 2004

Submicron nickel powders were prepared from aqueous solution under hydrothermal condition. The experimental conditions including the types of protective agents, concentration of the solution and the pH were studied in detail. Starting concentration of nickel ion is a dominant factor affecting particle size. It was shown that the subsequent addition of Poly Vinyl Pyrrolidone(PVP) and Sodium Dodecyle Sulfate(SDS) can help to disperse the nickel powder. X-ray diffraction and SEM were employed to characterize the products.

• Preventive Nutrition and Food Science
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• v.12 no.4
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• pp.229-233
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• 2007

This study was conducted to investigate the quality characteristics of cookies added with different levels of tomato powder. Cookies were prepared with five different levels of tomato powder (0, 2.5, 5.0, 7.5, and 10.0%) and the physicochemical properties were examined. The pH of cookie dough decreased significantly by the addition of tomato powder (p<0.05). Crude protein and ash content of the cookies containing 5.0, 7.5 and 10.0% tomato powder were significantly higher than those of control and those with 2.5% (p<0.05). The spread factor of control cookie was lower than that of cookies containing 5.0, 7.5, and 10.0% tomato powder. The incorporation of tomato powder in cookies lowered the lightness values but increased redness and yellowness values. Rheology testing showed that cookies with 5.0, 7.5, and 10.0% tomato powder had significantly lower hardness value than control. Sensory evaluation revealed that overall desirability scores were not significantly different between control and tomato powder added groups. Therefore, cookies with up to 10.0% added tomato powder would be as acceptable as control cookies without depressing cookie quality.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.144-145
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• 2006

A developed molybdenum hybrid-alloyed steel powder is based on a molybdenum prealloyed steel powder to which molybdenum powder particles are diffusion bonded. The sintered compact made of this powder has a finer pore structure than that of the conventional molybdenum prealloyed steel powder, because the ferritic iron phase $({\alpha}-phase)$ with a high diffusion coefficient is formed in the sintering necks where molybdenum is concentrated resulting in enhanced sintering. The rolling contact fatigue strength of the sintered and carburized compacts made of this powder improved by a factor of 3.6 compared with that of the conventional powder due to the fine pore structures.

• Journal of Powder Materials
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• v.23 no.2
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• pp.149-169
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• 2016

Additive manufacturing (AM) is defined as the manufacture of three-dimensional tangible products by additively consolidating two-dimensional patterns layer by layer. In this review, we introduce four fundamental conceptual pillars that support AM technology: the bottom-up manufacturing factor, computer-aided manufacturing factor, distributed manufacturing factor, and eliminated manufacturing factor. All the conceptual factors work together; however, business strategy and technology optimization will vary according to the main factor that we emphasize. In parallel to the manufacturing paradigm shift toward mass personalization, manufacturing industrial ecology evolves to achieve competitiveness in economics of scope. AM technology is indeed a potent candidate manufacturing technology for satisfying volatile and customized markets. From the viewpoint of the innovation technology adoption cycle, various pros and cons of AM technology themselves prove that it is an innovative technology, in particular a disruptive innovation in manufacturing technology, as powder technology was when ingot metallurgy was dominant. Chasms related to the AM technology adoption cycle and efforts to cross the chasms are considered.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.5
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• pp.605-612
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• 2013

The purpose of this study was to investigate the quality characteristics of maejakgwa prepared with Ligularia fischeri powder (0, 1, 3, 5, 7%) as a substitute for flour. The pH of maejakgwa dough significantly decreased in response to the addition of all levels of Ligularia fischeri powder. Spread factor values and water contents increased significantly with increasing amounts of Ligularia fischeri powder. In addition, the Hunter color L, a and b values decreased significantly with increasing amounts of Ligularia fischeri powder. Furthermore, hardness was increased significantly as the level of Ligularia fischeri powder increased. DPPH free radical scavenging activity increased significantly as the content of Ligularia fischeri powder increased (p<0.05). Finally, the results of the sensory properties indicated that maejakgwa containing 3% Ligularia fischeri powder had the highest scores. These results suggest that Ligularia fischeri powder can be applied to maejakgwa in order to achieve high quality and functionality.

• Journal of Powder Materials
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• v.29 no.2
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• pp.123-131
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• 2022

The purpose of this study is to improve the mechanical properties and develop manufacturing technology through self-soluble alloy powder flame spray coating on the surface of a run-out table roller for hot rolling. The roller surface of the run-out table should maintain high hardness at high temperatures and possess high wear, corrosion, and heat resistances. In addition, sufficient bonding strength between the thermal spray coating layer and base material, which would prevent the peel-off of the coating layer, is also an important factor. In this study, the most suitable powder and process for roll manufacturing technology are determined through the initial selection of commercial alloy powder for roll manufacturing, hardness, component analysis, and bond strength analysis of the powder and thermal spray coating layer according to the powder.