• 한국분말재료학회지
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• 제6권1호
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• pp.88-95
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• 1999

The purpose of this study is to investigate the manufacturing feasibility of WC-Co milling inserts via Powder Injection Molding (PIM) process. WC-Co is used in a wide variety of cutting tools due to its high hardness, stiffness, compressive strength and wear resistance properties. WC-Co parts for a high stress application were conventionally produced by the press and sinter method, which were Iimited to 2 dimensional shapes. Manufacturing WC-Co parts for a high stress application by PIM implies that tool efficiency can be highly improved due to increased freedom is design. P30 grade WC powder (WC-Co-TiC-TaC system) was mixed with RIST-5B133 binder and injection molded into milling inserts (Taegu Tech. Model WCMX 06T 308). The mean grain size of the powder was about 0.8$\mu$m. Injection molded specimens were debound by solvent extraction and thermal degradation method at various conditions. The specimens were sintered at 140$0^{\circ}C$ for 1 hr in vacuum. Carbon content, weight loss, dimensional change, and macro defects of the specimen were carefully monitored at each stage of the PIM process. PIMed WC-Co milling inserts reached 100% full density after sinteing. Its mechanical properties and micro-structures were comparable with the press and sintered milling insert. Carbon content of the sintered WC-Co insert was mainly determained by the atmosphere of thermal debinding. By controlling powder loading and injection molding condition, dimensional accuracy could be obtained within 0.4%. We confirm that PIM can not only be an alternative manufacturing method for WC-Co parts economically but also provide a design freedom for more effieient cutting tools.

• 한국산업융합학회 논문집
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• 제22권5호
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• pp.545-551
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• 2019

The purpose of this study was to investigate the effects of protease in kiwi fruit powder after freeze drying which has the ratio of 0%, 1%, 2%, and 3% on the tenderization of the bovine longissimus dorsi muscle. Beef loin chunks were marinated in distilled water (Control), 1% kiwi powder (K1), 2% kiwi powder (K2), and 3% kiwi powder (K3). As a result, the enzyme activities have shown to have higher activity (p<0.001) as the amount of freeze-dried kiwi powder increased. There are significant difference in pH (p<0.01), color of the beef were slightly different between the C (control) group and the sample groups. The cooking loss showed the highest value of K3 (p<0.001), and water holding capacity showed the highest value of K3. Furthermore, the sample groups exhibited lower shear force values compared with the control (p<0.001).

• 한국축산식품학회지
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• 제41권6호
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• pp.997-1011
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• 2021

The processing characteristics of freeze-dried pork powder as raw meat for comminuted meat products were compared with those of freeze-thawed pork. The tertiary structural properties, oxidation, and solubility of proteins in the freeze-dried pork powder were investigated. In addition, the properties of the emulsion gels manufactured with freeze-dried pork powder (GFD) and freeze-thawed pork (GFT) at 1.5% and 2.0% NaCl were evaluated. The surface hydrophobicity and intrinsic tryptophan fluorescence intensity of myofibrillar proteins between the freeze-dried pork powder and freeze-thawed pork were similar. However, freeze-dried pork powder had higher carbonyl compounds and lower solubility of sarcoplasmic and myofibrillar proteins than freeze-thawed pork (p<0.05). GFD had higher cooking loss than GFT in 2.0% NaCl, and lower hardness and a^* value of GFD were observed regardless of NaCl level (p<0.05). Moreover, GFD had higher malondialdehyde content than GFT at the two NaCl concentrations (p<0.05). Therefore, our study demonstrated that freeze-dried pork powder has lower functional properties than freeze-thawed pork as raw meat for comminuted meat products.

• 한국축산식품학회지
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• 제38권6호
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• pp.1179-1188
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• 2018

This study aimed to investigate the combined effect of using natural calcium mixtures and various binding ingredients as replacers for synthetic phosphate in ground pork products. We performed seven treatments: control (0.3% phosphate blend), treatment 1 (0.5% natural calcium mixtures [NCM, which comprised 0.2% oyster shell calcium and 0.3% egg shell calcium powder] and 0.25% egg white powder), treatment 2 (0.5% NCM and 0.25% whey protein concentrate), treatment 3 (0.5% NCM and 0.25% concentrated soybean protein), treatment 4 (0.5% NCM and 0.25% isolated soybean protein), treatment 5 (0.5% NCM and 0.25% carrageenan), and treatment 6 (0.5% NCM and 0.25% collagen powder). All the treatment mixtures had higher pH and lower cooking loss than the control, which was treated with phosphate. We found that NCM and binding ingredients had no negative effects on the moisture content, lightness, and yellowness of the cooked ground pork products. Treatments 3 and 4 showed significantly lower CIE $a^*$ values than the control. Treatments 2 and 6 improved the textural properties of the products. In conclusion, the combination of NCM with whey protein concentrate or collagen powder could be suitable for producing phosphate-free meat products.

• 한국식생활문화학회지
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• 제37권4호
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• pp.354-362
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• 2022

The purpose of this study was to investigate the possibility of using air potato (Dioscorea bulbifera) powder to make sponge cakes. The sponge cake batter was made by adding 0, 10, 20, 30, and 40% of air potato powder, and the resultant anti-oxidative properties and quality characteristics were analyzed. The study showed that the height, batter yield, and loss rate of sponge cakes decreased as increasing amounts of air potato powder were added, but the weight, viscosity, moisture content, and specific gravity increased. An evaluation of the color showed that the L and b values were highest in the control group but the a value was highest in the 40% group. There was no significant difference between samples in terms of cohesiveness, although the study showed a significant increase in the hardness, chewiness, and gumminess as the quantity of air potato powder in the sponge cakes increased. The total polyphenol content and DPPH radical scavenging activity increased noticeably as more air potato powder was added to the sponge cakes. The results thus showed that the study groups with the addition of air potato powder showed higher antioxidant activity than the control group.

• 한국식생활문화학회지
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• 제25권6호
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• pp.633-638
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• 2010

The objective of this study was to assess the physicochemical characteristics of morning rolls containing various levels (0, 2, and 4%) of Makgeolli lees extract powder, which has nutritional and health effects. The results demonstrated that pH, moisture content, volume, weight, and baking loss rate of morning rolls were not significantly different among the groups. In the morning rolls with 4% Makgeolli lees extract powder, the Hunter's color 'a' (redness), but not L (lightness) or b (yellowness), was significantly higher than that in the other two groups. After estimating the texture quality of morning rolls, hardness, chewiness, and gumminess decreased significantly with added Makgeolli lees extract powder, but springiness was not significantly different. The results of the sensory test showed that appearance and texture increased as more Makgeolli lees extract powder was added, and that the overall acceptability score and air cell uniformity score for 2% and 4% Makgeolli lees extract powder morning rolls were significantly higher than those of controls. These results indicate that the texture and sensitivity of morning rolls can be increased by adding Makgeolli lees extract powder without affecting the overall quality.

• 한국식품저장유통학회지
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• 제31권2호
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• pp.256-266
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• 2024

This study examined the effects of chestnut powder content (2.5%, 5%, 7.5%, and 10%) on the antioxidant activity and quality characteristics of rice muffins. With the increasing chestnut powder content, the total polyphenol content, flavonoid content, antioxidant activity (determined by radical scavenging activity and reducing power), hardness, gumminess, chewiness, and overall acceptability (determined by sensory evaluation) increased, whereas the moisture content, pH, specific volume, and cooking loss decreased. Regarding color, chestnut powder content was negatively correlated with L and b and positively correlated with a. Notably, overall acceptability abruptly decreased to its minimum at 10%. Thus, adding powder at loadings of <7.5% improved the antioxidant activity and acceptability of rice muffins. Our results can be used as preparatory data for developing a rice muffin model.

• 한국자기학회지
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• 제15권3호
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• pp.191-197
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• 2005

철계 비정질 합금 리본을 분쇄한 뒤 상온 압축성형을 통하여 분말코아를 제조할 때 로터밀과 볼밀의 두 가지 분말제조 공정을 사용하여 만든 분말의 형상을 관찰하고, 또 이들을 이용한 분말코아의 자기적 및 전기적 특성과 미세구조를 조사하였다. 로터밀을 사용한 경우 실효투자율의 크기는 볼 밀링한 경우보다 낮았으나 이의 주파수 의존성 및 품질계수는 볼밀의 경우보다 우수하였으며 자심손실 또한 더 작았다. 한편 로터밀을 사용하여 만든 분말은 크기가 균일하고 가장자리는 강한 전단가공을 받아 완만한 곡선을 지닌 등축형을 이루고 있는 반면 볼밀을 사용한 경우는 크기가 상대적으로 불규칙하면서 작은 분말이 많고 가장자리는 날카로운 형상을 하고 있었다. 로터밀로 만든 분말코아의 낮은 투자율은 밀링시 심한 전단에 의해 발생하는 큰 내부응력의 축적에 기인하는 것으로 보여진다. 한편 로터 밀링을 통해 만든 분말코아의 경우 투자율은 상대적으로 낮지만 전기저항의 측정 및 미세구조의 관찰로부터 보다 양호한 절연상태가 확보되어 높은 주파수에 이르기까지 투자율이 유지되면서 적은 자심손실이 얻어진 것으로 판단되었다. 분말코아의 자기적 안정성을 나타내는 직류중첩특성 또한 로터밀의 경우가 볼 밀링한 경우보다 우수하였다.

• 한국식품조리과학회지
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• 제22권6호통권96호
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• pp.905-913
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• 2006

The properties of water soluble powder of propolis(WSP), made with different levels(0, 20, 40, 60, 80%) of ethanol extract of propolis(EEP) and hydrocolloid were investigated, along with the quality changes of its bread after 7 days' of storage at $30^{\circ}C$ The yield of WSP containing 40% EEP treated at $160^{\circ}C$ was the highest at 59.3% and the brown color of all the powders tended to be darkened with increasing EEP content. The turbidity of WSP treated at higher temperature was decreased in its aqueous solution (10%, w/w), and this was considered to be due to the presence of minute nonsoluble particles. Antioxidative activities determined by DPPH(1,1-diphenyl-2-picrylhydrazyl) were the lowest in WSP treated at $140^{\circ}C$, while those of the WSP samples prepared at 160 and $180^{\circ}C$ were as high as that of WSP containing more than 40% EEP, regardless of EEP concentration. The propolis breads with added WSP made at $160^{\circ}C$ were selected as the most desirable powder for subsequent study. Bread with WSP40 was the heaviest while the volume loss of WSP80 was the greast after baking. The moisture contents of the propolis bread were drastically decreased until 3 days' of storage, but it was thought that WSP might be ineffective for the prevention of moisture loss. The pH of breads without EEP was decreased after 3 days' of storage, while that of the WSP breads remained almost unchanged until 5 days' of storage. Total bacterial counts also exhibited decay levels during the storage. In conclusion, water soluble powder of propolis is useful as a natural antioxidative and antibacterial material in various types of food.

• Advances in concrete construction
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• 제8권1호
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• pp.21-31
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• 2019

The rich recipe of ultra high performance concrete (UHPC) offers the higher mechanical, durability and dense microstructure property. The variable like cement/sand ratio, amount of supplementary cementitious material, water/binder ratio, amount of fiber etc. alters the UHPC hardened properties to any extent. Therefore, to understand the effects of these variables on the performance of UHPC, inevitably a stage-wise development is required. In the present experimental study, the effect of sand/cement ratio, the addition of finer material (fly ash and quartz powder) and, hybrid fiber on the fresh, compressive and microstructural property of UHPC is evaluated. The experiment is conducted in three phases; the first phase evaluates the flow value and strength attainment of ingredients, the second phase evaluates the efficiency of finer materials (fly ash and quartz powder) to develop the UHPC and the third phase evaluate the effect of hybrid fiber on the flow value and strength of ultra high performance hybrid fiber reinforced concrete (UHP-HFRC). It has been seen that the addition of fly ash improves the flow value and compressive strength of UHPC as compared to quartz powder. Further, the usage of hybrid fiber in fly ash contained matrix decreases the flow value and improves the strength of the UHP-HFRC matrix. The dense interface between matrix and fiber and, a higher amount of calcium silicate hydrate (CSH) in fly ash contained UHP-HFRC is revealed by SEM and XRD respectively. The dense interface (bond between the fiber and the UHPC matrix) and the higher CSH formation are the reason for the improvement in the compressive strength of fly ash based UHP-HFRC. The differential thermal analysis (DTA/TGA) shows the similar type of mass loss pattern, however, the amount of mass loss differs in fly ash and quartz powder contained UHP-HFRC.