• 한국식품조리과학회지
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• 제18권5호
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• pp.487-494
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• 2002

This study was conducted to investigate the thermal stability of water-soluble and fat-soluble vitamins dissolved in water and milk by various heat treatments. Vitamin samples were prepared by dissolving them in water and milk at various concentrations, and were heat treated for 30 min at 65$\^{C}$, 15 sec at 85$\^{C}$, 5 sec at 100$\^{C}$, 121$\^{C}$ at 15 min, the levels of residual vitamin were measured by using HPLC. Milk samples were fortified with vitamins before and after UHT treatment. As heating over 100$\^{C}$, riboflavin in water were destructed more than 92% but fortified in milk showed less than 20% destruction, suggesting that riboflavin was protected by milk components. Also retinol heated ever 100$\^{C}$ was more stable in milk than in water. L-Ascorbic acid and cholecalciferol(D$_3$) showed a similar destruction rate in water and in fortified milk. L-ascorbic acid was easily destructed by UHT treatment. Destruction of thiamin and tocopherol was increased in fortified milk. Among tour capsulated water-soluble vitamins, L-ascorbic acid was much more stable compared with powder form. Nicotinic acid and folic acid either in capsule or powder form showed a slight destruction by heat treatment. The results suggested that the fortification of unstable vitamins such as L-ascorbic acid, thiamin, tocopherol and cholecalciferol(D$_3$) should be made in milk after heat treatment.

• 한국분말재료학회지
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• 제21권1호
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• pp.7-15
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• 2014

This study investigated the densification behavior of rhenium alloys including W-25 wt.%Re and Re-2W-1Ta (pure Re) during sintering. The dilatometry experiments were carried out to obtain the in-situ shrinkage in $H_2$ atmosphere. The measured data was analyzed through shrinkage, strain rate and relative density, and then symmetrically treated to construct the linearized form of master sintering curve (MSC) and MSC as a well-known and straightforward approach to describe the densification behavior during sintering. The densification behaviors for each material were analyzed in many respects including apparent activation energy, densification parameter, and densification ratio. MSC with a minimal set of preliminary experiments can make the densification behavior to be characterized and predicted as well as provide guideline to sinter cycle design. Considering the results of linearized form and MSC, it was confirmed that the W-25 wt.%Re compared to Pure Re is more easily densified at the relatively low temperature.

• 한국분말재료학회지
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• 제26권6호
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• pp.528-538
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• 2019

The transition from "More-of-Less" markets (economies of scale) to "Less-of-More" markets (economies of scope) is supported by advances of disruptive manufacturing and reconfigurable-supply-chain management technologies. With the prevalence of cyber-physical manufacturing systems, additive manufacturing technology is of great impact on industry, the economy, and society. Traditionally, backbone structures are built via bottom-up manufacturing with either pre-fabricated building blocks such as bricks or with layer-by-layer concrete casting such as climbing form-work casting. In both cases, the design selection is limited by form-work design and cost. Accordingly, the tool-less building of architecture with high design freedom is attractive. In the present study, we review the technological trends of additive manufacturing for construction-scale additive manufacturing in particular. The rapid tooling of patterns or molds and rapid manufacturing of construction parts or whole structures is extensively explored through uncertainties from technology. The future regulation still has drawbacks in the adoption of additive manufacturing in construction industries.

• 한국세라믹학회지
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• 제27권4호
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• pp.501-512
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• 1990

Al2O3 and 0.25wt% MgO-doped Al2O3 powders were made from the alcohol solution of Al(NO3)3.9H2O and Mg(NO3)2.6H2O by spray pyrolysis method. Each powder was prepared at 900 and 100$0^{\circ}C$. Powders prepared at 90$0^{\circ}C$ were amorphous phase, but prepared at 100$0^{\circ}C$ wre mainly ${\gamma}$-Al2O3 crystalline form. Particle size of the MgO-doped Al2O3 powders was in the range of 0.2-2${\mu}{\textrm}{m}$, but undooped powders shwoed comparatively wider range of particle size. All the powders prepared at 900 and 100$0^{\circ}C$ were transformed to $\alpha$-Al2O3 crystalline form by calcination at 110$0^{\circ}C$ for 1hr. Each powder was sintered at 1600, 1650 and 1$700^{\circ}C$ for 2hrs. MgO-doped Al2O3 body sintering at 1$650^{\circ}C$ showed 99% of relative density but undooped Al2O3 showed 95% of relative density, even sintered at higher temperature of 1$700^{\circ}C$.

• 한국분말재료학회지
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• 제9권1호
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• pp.19-24
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• 2002

This paper reports the results of an investigation into the effect of Cu additions upon the nano-crystallization behaviour of an Al-Y-Ni alloy. 1 at.% Cu was added to a base alloy of Al/sub 88/Y₄Ni/sub 8/ either by substitution for Al to form Al/sub 87/Y₄Ni/sub 8/Cu₁, or by substitution for Ni to form Al/sub 88/Y₄Ni/sub 7/Cu₁. Consistent with previous findings in the literature, the substitution of Cu for Al was found to increase the thermal stability of the amorphous phase whereas the substitution of Cu for Ni was found to decrease its thermal stability. Comparing the microstructures of these alloys after heat treatment to produce equivalent volume fractions of Al nanocrystals showed average grain sizes of 14 nm, 12 nm and 9 nm for the alloys Al/sub 88/Y₄Ni/sub 8/, Al/sub 87/Y₄Ni/sub 8/Cu₁respectively. The effect of Cu in refining the size of the nanocrystals was attributed to enhanced nucleation increasing the number density of the nanocrystals, rather than diffusion limited or interface limited growth.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1110-1111
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• 2006

[ $Ti_3SiC_2$ ] was coated with $Al_2O_3$, MgO and $SiO_2$ respectively by sol-gel method and cured at 900 and $1200^{\circ}C$. The coated oxides did not react with $Ti_3SiC_2$ at $900^{\circ}C$ but reacted with it to form $TiC_x$ at $1200^{\circ}C$. The specimen coated with $SiO_2$ at $900^{\circ}C$ formed a dense protecting layer and showed the best oxidation resistance at $800^{\circ}C$ in air. However, the dense protecting layers did not form in $Al_2O_3$ and MgO coated specimens cured even at $900^{\circ}C$. MgO coated specimen showed the worst improvement in the oxidation resistance because the reactivity of MgO with $Ti_3SiC_2$ was highest. On the other hand, the electrical conductivities were measured in MgO and $Al_2O_3$ coated specimens to have TiCx but could not be measured in the $SiO_2$ coated ones because of the nonconductive dense protected layers.

• 한국분말재료학회지
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• 제25권5호
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• pp.420-425
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• 2018

Core-shell structured nanoparticles are garnering attention because these nanoparticles are expected to have a wide range of applications. The objective of the present study is to improve the coating efficiency of gold shell formed on the surface of silica nanoparticles for $SiO_2@Au$ core-shell structure. For the efficient coating of gold shell, we attempt an in-situ synthesis method such that the nuclei of the gold nanoparticles are generated and grown on the surface of silica nanoparticles. This method can effectively form a gold shell as compared to the conventional method of attaching gold nanoparticles to silica particles. It is considered possible to form a dense gold shell because the problems caused by electrostatic repulsion between the gold nanoparticles in the conventional method are eliminated.

• 한국분말재료학회지
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• 제26권3호
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• pp.225-230
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• 2019

To develop Taraxacum platycarpum extract (TP)-loaded particles for tablet dosage form, various TP-loaded particles composed of TP, dextrin, microcrystalline cellulose (MCC), silicon dioxide, ethanol, and water are prepared using a spray-drying method and fluid-bed-drying method. Their physical properties are evaluated using angle of repose, Hausner ratio, Carr's index, hardness, disintegrant time, and scanning electron microscopy. Optimal TP-loaded particles improve flowability and compressibility. Furthermore, 2% silicon dioxide gives increased flowability and compressibility. The formula of TP-loaded fluid-bed-drying particles at a TP/MCC/silicon-dioxide amount of 5/5/0.2 improves the angle of repose, Hausner ratio, Carr's index, hardness, and disintegrant time as compared with the TP-loaded spray-drying particles. The TP-loaded fluid-bed-drying particles considerably improve flowability and compressibility ($35.10^{\circ}$ vs. $40.3^{\circ}$, 0.97 vs. 1.17, and 18.97% vs. 28.97% for the angle of repose, Hausner ratio, and Carr's index, respectively), hardness (11.34 vs. 4.7 KP), and disintegrant time (7.4 vs. 10.4 min) as compared with the TP-loaded spray-drying particles. Thus, the results suggest that these fluid-bed-drying particles with MCC and silicon dioxide can be used as powerful particles to improve the flowability and compressibility of the TP.

• 한국가금학회지
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• 제51권2호
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• pp.47-56
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• 2024

본 연구는 콜리플라워 분말의 첨가가 저지방 닭가슴살 소시지에 미치는 품질 특성을 알아보기 위해 수행되었다. 콜리플라워 분말의 첨가는 소시지 반죽의 pH를 상승시켰으며(P<0.05), 가열 감량 및 저장 감량의 총합을 감소시켰다(P<0.05). 저지방 처리군에서 첨가된 수분의 증가로 인해 낮은 경도를 나타냈으며, 저장 중 수분 손실로 인해 대조구를 제외한 모든 처리군에서 경도가 증가하였다. 콜리플라워 분말의 첨가는 저장 30일차에서 MDA 생성을 유의적으로 감소시켰다. 관능평과 결과, 모든 평가항목에서 콜리플라워를 첨가한 처리구가 대조구에 비해 유의적으로 낮은 평가를 받았다(P<0.05). 따라서 본 연구 결과, 콜리플라워 분말을 이용하여 보수력과 지질 산패도가 개선된 저지방 닭가슴살 소시지의 제조가 가능할 것으로 생각되나, 콜리플라워 분말을 첨가한 저지방 닭가슴살 소시지의 관능적 특성에 대한 소비자의 기호도가 낮기 때문에 추가적인 연구 및 개발이 필요할 것으로 사료된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제40권1호
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• pp.22-27
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• 2020

Silkworm powder was prepared from 3^rd day of 5^th instar silkworm through various drying technology including freeze drying, hot wind drying, infrared drying, and microwave drying. The shape of silkworm dried was different with the drying methods. Freeze drying and microwave drying silkworm looked its original form, but hot wind drying and infrared drying silkworm looked shriveled and crumpled. The color of silkworm powder freeze-dried changed from yellowish green to hazel with lowering freezing temperature. Heavy metals including Pb, Cd, As, and Hg were lower the food criteria. The results of 1-deoxynojirimycin analysis was shown that BaekOkJam and GoldenSilk silkworm powder was satisfied the criteria of functional food, but YeonNokJam silkworm powder was lower than the criteria. The amino acid composition of silkworm was similar regardless of the frozen temperature in freeze drying process.