The powder injection molding process having advantages in manufacturing three-dimensional precision parts essentially requires a debinding process before sintering to remove the binders used for preparing feedstock. In this study, powder injection molding of translucent alumina was performed, and carbon dioxide (CO2) is used as a supercritical fluid that makes it possible to remove a large amount of binder, which is paraffin wax. The relationship between the optical property of translucent alumina and the debinding condition (temperature and pressure) of supercritical CO2 was investigated. As temperature and pressure increased, extraction rate of the binder showed rising tendency and average grain size after sintering process was relatively fine. On the other hand, optical transmittance was reduced. As a result, the debinding condition at 50˚C and 20 MPa that represents the lowest extraction rate, 8.19x10-3m2/sec, corresponds to the largest grain size of 14.7μm and the highest optical transmittance of 45.2%.

투명 전도성 산화물로서 알루미늄과 붕소가 함께 도핑된 아연산화물(AZOB)이 900℃에서 분무 열분해법에 의해 제조되었다. 얻어진 마이크론 크기의 AZOB 분말은 알루미늄, 붕소 및 아연의 수용액으로부터 얻어진다. 분무 열분해로 얻어진 마이크론 크기의 AZOB 분말은 700℃에서 두 시간동안의 후 소성 과정과 24 시간 동안의 볼 밀링을 통해 나노 크기의 AZOB으로 변환된다. AZOB을 구성하는 일차 입자의 크기를 Debye-Scherrer 식에 의해 계산하였고 압축된 AZOB 펠렛의 표면 저항을 측정하였다.

마이크론 크기를 가지는 ITO(indium tin oxide) 입자들은 인듐과 틴의 수용성 전구체들과 유기 첨가제를 분무 열분해하여 얻었다. 유기 첨가제로서는 에틸렌글리콜과 시트르산을 이용하였다. 분무 열분해 시 에틸렌글리콜과 시트르산과 같은 유기첨가제를 첨가하지 않고 얻어진 ITO 입자들은 구형이며 속이 꽉찬 형태를 가지는데 비해 유기 첨가제를 첨가하여 분무 열분해를 하면 얻어지는 ITO 입자들은 유기 첨가제의 양이 증가 할수록 껍질이 얇고 다공성이 증대된 중공 입자가 얻어진다. 유기첨가제를 첨가하지 않고 분무 열분해를 통해 얻어지는 마이크론 크기를 가지는 ITO는 700℃에서 두 시간 동안의 후소성과 24 시간동안의 습식 볼밀링에 의해 나노 크기의 ITO로 전환되지 않으나, 유기첨가제를 첨가하고 분무 열분해를 통해 얻어지는 마이크론 크기를 가지는 ITO는 700℃에서 두 시간 동안의 후소성과 24 시간 동안의 습식 볼밀링에 의해 나노 크기의 ITO로 쉽게 전환되었다. 응집된 나노 크기의 ITO의 일차 입자의 크기를 Debye-Scherrer 식에 의해 계산하였고 ITO 입자를 압축하여 만든 펠렛의 표면저항을 측정하였다.

This study was performed to determine the optimal composition of muffins added with dropwort powder, egg and sugar. The experiment was designed based on BBD (Box-behnken design), and evaluation was carried out by means of RSM (response surface methodology), consisting of 13 experimental points with three replicates each for three independent variables dropwort powder, eggs and sugar. Using F-test, height, moisture, 1,1-diphenyl-2picriylhydrazyl (DPPH) radical scavenging activity, L-value, a-value, springiness, cohesiveness, chewiness, brittleness, color, and appearance acceptability were expressed as a linear model, whereas pH, b-value, flavor, taste, and texture were expressed as a quadratic model. After swallow and overall acceptability were expressed as a 2FI model. As dropwort powder content increased, 1,1-diphenyl-2picriylhydrazyl (DPPH) radical scavenging activity increased. Increasing amounts of dropwort powder led to reduction of sensory scores for color, appearance, flavor, taste, and texture quality. The optimum formulation determined by the numerical and graphical methods were similar: dropwort powder 6 g, egg 77 g, and sugar 60 g.

Effect of oxygen content in the ultrafine tungsten powder fabricated by electrical explosion of wire method on the behvior of spark plasma sintering was investigated. The initial oxygen content of 6.5 wt% of as-fabricated tungsten powder was reduced to 2.3 and 0.7 wt% for the powders which were reduction-treated at 400˚C for 2 hour and at 500˚C for 1h in hydrogen atmosphere, respectively. The reduction-treated tungsten powders were spark-plasma sintered at 1200-1600˚C for 100-3600 sec. with applied pressure of 50 MPa under vacuum of 0.133 Pa. Maximun sindered density of 97% relative density was obtained under the condition of 1600˚C for 1h from the tungsten powder with 0.7 wt% oxygen. Sintering activation energy of 95.85kJ/mol-1 was obtained, which is remarkably smaller than the reported ones of 380~460kJ/mol-1 for pressureless sintering of micron-scale tungsten powders.

In this study, the reduction kinetics and behaviors of oxides in the water-atomized iron powder have been evaluated as a function of temperature ranging 850-1000˚C in hydrogen environment, and compared to the reduction behaviors of individual iron oxides including Fe2O3, Fe3O4 and FeO. The water-atomized iron powder contained a significant amount of iron oxides, mainly Fe3O4 and FeO, which were formed as a partially-continuous surface layer and an inner inclusion. During hydrogen reduction, a significant weight loss in the iron powder occurred in the initial stage of 10 min by the reduction of surface oxides, and then further reduction underwent slowly with increasing time. A higher temperature in the hydrogen reduction promoted a high purity of iron powder, but no significant change in the reduction occurred above 950˚C. Sequence reduction process by an alternating environment of hydrogen and inert gases effectively removed the oxide scale in the iron powder, which lowered reduction temperature and/or shortened reduction time.

In this research, magnesium powder was prepared by gas atomizing. Refinement behaviors of magnesium powder produced under different conditions were investigated using a mechanical milling (attrition milling) process. Analyses were performed to assess the characterization and comparison of milled powder with different steel ball sizes and milling times. The powders were analyzed by field emission scanning electron microscope, apparent density and powder fluidity. The particle morphology of the Mg powders changed from spherical particles of feed metals to irregular oval particles, then plate type particles, with an increasing milling time. Because of the HCP structure, deformation occurs due to the existence of the easily breakable C-axis perpendicular to the base, which results in producing plate-type powders. An increase in ball size and the impact energy of the magnesium powder maximizes the effect of refinement. Furthermore, it is possible to improve the apparent density and fluidity according to the smoothness of the surface of the initial powder.

Sesame is a major cooking oil crop in Korea. One of the primary problems in sesame cultivation is low healthy stand establishment due to the occurrence of seedling rot and damping-off resulting from a complex of soil-borne pathogens in the field. To address the problem, the bioformulation of Pseudomonas fluorescens M45 was prepared in powder form using clay and vermiculite, and was evaluated for its effect on biological control of soil-borne pathogens in sesame cultivation. In the petri dish trial, the emergence rate was overall good (> 92%) regardless of seeds being pelleted and/or M45-treated. In both pot and field trials containing disease-conducive soils, seed-pelleting substantially reduced emergence rate, whereas seed-pelleting with M45 significantly improved the emergence rate (> 26%). The emergence rate of sesame seeds treated with the strain M45 was greater than 30% regardless of seed pelletization. We also found that M45r colonized in the roots at the density of 1.6×105 cfu/g. With aid of the bioformulation, however, root colonization of the strain was significantly increased to 4.0×106 cfu/g. The powder formulation with strain M45 enhanced the rate of healthy stand establishment in disease-conducive soil. Therefore, bioformulation with strain M45 is a promising method to overcome problems associated with the successive cultivation of sesame.

This study investigated the quality characteristics of cookies containing capsaicin, the main source of spicy taste in pepper, which is well known for its various functions such as anti-oxidant, anti-cancer, anti-inflammatory, and anti-obesity activities, as well as pain-relief effect. Cookie samples were made by adding the capsaicin powder at different levels, including 40 mg% (C1), 85 mg% (C2), and 150 mg% (C3). In this study, measurement of the moisture, pH, color, spread factor, hardness, anti-oxidant activity, and sensory evaluation of the cookies was carried out. The results showed that the anti-oxidant activity increased when more capsaicin powder was added to the cookies (p＜0.001). The moisture also increased with increasing capsaicin powder content (p＜0.05), while the pH did not show any significant changes. As for the colors, the L value and b value decreased as more capsaicin powder was added, while the a value increased. The spread factor also increased significantly with the increase of capsaicin powder (p＜0.01). Although the hardness increased with capsaicin powder content, no statistically significant differences were observed among the various cookies. In the sensory evaluation, Cookies containing 40 mg of capsaicin obtained the highest score in color, while cookies containing 150 mg of capsaicin showed the highest score in taste, texture, and overall acceptability.

The purpose of this study was to investigate the quality characteristics of white bean based Yanggaeng containing various levels of pomegranate powder (0, 2, 4 and 8%, w/w). The pH values of Yanggaeng containing pomegranate powder were found to decrease when increasing the amount of pomegranate powder. However, moisture and sugar contents were increased (p＜0.05). For color values, both L and b values were reduced by increasing the amount of pomegranate powder, while a values were increased significantly (p＜0.05). In textural properties, the addition of pomegranate powder resulted in the increase of hardness, chewiness and gumminess, while cohesiveness and springiness decreased. Antioxidant activities, evaluated by DPPH radical scavenging capacity, and total phenolic substances content increased when increasing the amount of pomegranate powder. Results of descriptive analysis showed that by increasing the amount of pomegranate powder, some attributes such as the intensity of the flavor, sourness, hardness and chewiness increased (p＜0.05), but there was no statistically significant difference in sweetness. In a preference test, Yanggaeng containing 4% pomegranate powder appeared to be the most preferred for all attributes tested including overall acceptability. It was concluded that Yanggaeng containing pomegranate can be prepared with good sensory properties and antioxidant activities, and the addition of 4% pomegranate powder was found to be ideal.

콩단백질을 이용한 콩고기 제조시 콩의 전처리 조건에 따른 품질 특성을 비교하고자 생콩, 증자콩 및 볶은콩 분말을 각각 동일 비율로 첨가한 콩고기의 품질관련 인자를 분석하였다. 관능평가 결과 생콩 분말로 제조한 콩고기의 기호도가 가장 낮았으나 견고성, 씹힘성 및 검성은 생콩으로 제조한 시료가 가장 높았다. L 값은 증자콩 분말로 제조한 콩고기에서 63.71±3.81로 가장 높았고, a값은 볶은콩분말로 제조한 콩고기에서 10.0±0.61, b값은 유사한 범위였다. 수분함량은 증자콩과 볶은콩 분말로 제조한 콩고기에서 유사한 범위이며 조지방은 증자콩 분말, 탄수화물은 생콩 분말로 각각 제조한 콩고기에서 가장 높았다. 아미노산의 총량은 생콩 분말로 제조한 콩고기가 89,863.79 mg/kg으로 가장 높았고, 지방산의 총량은 3916.9 mg/100g으로 증자콩 분말로 제조한 콩고기에서 가장 높았다. 총 flavonoids, isoflavone과 같은 생리활성 물질의 함량은 생콩 분말로 제조한 콩고기에서 가장 높았고, 항산화 활성은 증자콩으로 제조한 콩고기에서 더 높았다.

The quality characteristics of noodles made from domestic Korean wheat flour added with 0, 1, 3, 5% cactus Chounnyuncho (Opuntia humifusa) powder were investigated. The water absorption and peak time of dough, as determined by farinography, increased with higher cactus powder content. Stability and elasticity of dough decreased as fermentation proceeded. Cooking characteristics of noodles made from dough such as weight, water absorption, and volume decreased with higher cactus powder content. The turbidity of cooked water increased significantly with 5% cactus powder content. For color test, L-value decreased while a-value and b-value increased with higher cactus powder content. In texture analyses, hardness, adhesiveness, springiness, cohesiveness, and gumminess increased with higher cactus powder content. In the sensory test, noodles containing 3% cactus powder were the most preferred.

This study was conducted to promote the utilization of fish paste added with green laver powder as a food product. The tested concentrations of green laver powder were 0, 3, 5, and 7%. The pH of the samples ranged from 6.71 to 6.90, and moisture content ranged from 70.03 to 70.57%. The L and a values of the samples decreased as the concentration of green laver powder increased and b value increased. Folding test in all test samples showed AA that mean good flexibility. In the texture meter test, hardness, cohesiveness, and springiness increased according to increasing concentration of green laver powder. However, gumminess and brittleness of the fish paste decreased upon addition of green laver powder. In the sensory evaluation, fish paste prepared with 5% green laver powder was preferred over other fish pastes. These results suggest that green laver powder can be applied to fish paste for the purpose of high quality and functionality.

A powder-in-sheath rolling (PSR) process utilizing a copper alloy tube was applied to a fabrication of a multi-walled carbon nanotube (CNT) reinforced aluminum matrix composite. A copper tube with an outer diameter of 30 mm and a wall thickness of 2 mm was used as a sheath material. A mixture of pure aluminum powders and CNTs with the volume contents of 1, 3, 5 vol% was filled in the tube by tap filling and then processed to 93.3% height reduction by a rolling mill. The relative density of the CNT/Al composite fabricated by the PSR decreased slightly with increasing of CNTs content, but showed high value more than 98%. The average hardness of the 5%CNT/Al composite increased more than 3 times, compared to that of unreinforced pure Al powder compaction. The hardness of the CNT/Al composites was some higher than that of the composites fabricated by PSR using SUS304 tube. Therefore, it is concluded that the type of tube affects largely on the mechanical properties of the CNT/Al composites in the PSR process.

The effects of particle size of Li-Si alloy and LiCl-KCl addition as a binder phase for raw material of anode were investigated on the formability of the thermal battery anode. The formability was evaluated with respect to filling density, tap density, compaction density, spring-back and compressive strength. With increasing particle size of Li-Si alloy powder, densities increased while spring-back and compressive strength decreased. Since the small spring-back is beneficial to avoiding breakage of pressed compacts, larger particles might be more suitable for anode forming. The increasing amount of LiCl-KCl binder phase contributed to reducing spring-back, improving the formability of anode powder too. The control of particle size also seems to be helpful to get double pressed pellets, which consisted of two layer of anode and electrolyte.

The crystallization effects of boron (B) powder on the phase, full width at half maximum (FWHM) values, and critical properties were investigated for in-situ reacted MgB2 bulk superconductors. The semi-crystalline B powder was heat-treated at different temperatures of 1000, 1300 and 1500˚C for 5 hours in an Ar atmosphere. Then, using as-received and heat-treated B powders, the MgB2 samples were prepared at 600˚C for 40 hours in an Ar atmosphere. As the heat-treatment temperature of the B powder increased, both the particle size of the B powder and crystalline phase increased. In the case of MgB2 samples using B powders heat-treated at above 1300˚C, unreacted magnesium (Mg) and B remained due to the improved crystallinity of the B powder. As the heat-treatment temperature of B powder increased, the critical current density of MgB2 decreased continuously due to the reduction of grain boundary density and superconducting volume caused by unreacted Mg and B.

Aloe is an attractive potential food source because it has functional uses. It has been widely used as a well-being food and drink. The antioxidant activity was estimated by measuring DPPH free radical scavenging activity. We investigated the quality characteristics of cookies prepared by adding various concentrations of aloe powder (0%, 1%, 3%, 5%, all w/w) as a substitute for flour. In this study, the DPPH free radical scavenging activity, moisture content, and hardness of cookies significantly increased with increasing aloe powder, while the pH, spread factor and L and b values slightly decreased. Sensory evaluation scores in terms of texture were shown to be very similar statistically, but color, flavor, taste, and overall acceptability scores were lower than the control. As a result of this study, the quality of cookies with the addition of 1% aloe powder were the most suitable in terms of taste, flavor, texture, and sensory properties.