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        검색결과 2,183

        103.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Titanium is the ninth most abundant element in the Earth’s crust and is the fourth most abundant structural metal after aluminum, iron, and magnesium. It exhibits a higher specific strength than steel along with an excellent corrosion resistance, highlighting the promising potential of titanium as a structural metal. However, titanium is difficult to extract from its ore and is classified as a rare metal, despite its abundance. Therefore, the production of titanium is exceedingly low compared to that of common metals. Titanium is conventionally produced as a sponge by the Kroll process. For powder metallurgy (PM), hydrogenation-dehydrogenation (HDH) of the titanium sponge or gas atomization of the titanium bulk is required. Therefore, numerous studies have been conducted on smelting, which replaces the Kroll process and produces powder that can be used directly for PM. In this review, the Kroll process and new smelting technologies of titanium for PM, such as metallothermic, electrolytic, and hydrogen reduction of TiCl4 and TiO2 are discussed.
        4,000원
        104.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted in order to investigate the antioxidant and antimicrobial activity of Solanum nigrum L. fruit powder after undergoing different extraction solvent processes. The total phenolic content of Solanum nigrum L. fruit powder measured a 14.66 GAE mg/g after undergoing ethanol extraction, and the total flavonoid content measured at 201.23 mg CE/g when undergoing ethanol extraction. The ABTS radical scavenging activity was 160.38~209.53 TEAC umol/g, and the DPPH radical scavenging activity was 53.99~90.76 TEAC umol/g, which indicated a higher level of antioxidant power in the ethanol extract as opposed to in the water extract. The FRAP (ferric reducing antioxidant power) of Solanum nigrum L. fruit powder was 115.58~194.58 TEAC umol/g, and B. subtilis KCTC 2189 showed greater antimicrobial activity in the ethanol extract (concentration 200 ug/uL) as opposed to the water extract. Solanum nigrum L. fruit powder revealed differences in antioxidant and antimicrobial activity between the different extraction solvents. In particular, ethanol extract had higher antioxidant and antibacterial activity, meaning it is more favorable for usage as a functional food material.
        4,000원
        105.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, AlSi10Mg alloy powders are synthesized using gas atomization and sieving processes for powder bed fusion (PBF) additive manufacturing. The effect of nozzle diameter (ø = 4.0, 4.5, 5.0 and 8.0 mm) on the gas atomization and sieving size on the properties of the prepared powder are investigated. As the nozzle diameter decreases, the size of the manufactured powder decreases, and the uniformity of the particle size distribution improves. Therefore, the ø 4.0 mm nozzle diameter yields powder with superior properties. Spherically shaped powders can be prepared at a scale suitable for the PBF process with a particle size distribution of 10–45 μm. The Hausner ratio value of the powder is measured to be 1.24. In addition, the yield fraction of the powder prepared in this study is 26.6%, which is higher than the previously reported value of 10–15%. These results indicate that the nozzle diameter and the post-sieve process simultaneously influence the shape of the prepared powder as well as the satellite powder on its surface.
        4,000원
        106.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Powder quality, including high flowability and spherical shape, determines the properties of additively manufactured products. Therefore, the cheap production of high-quality powders is critical in additive manufacturing. Radio frequency plasma treatment is an effective method to fabricate spherical powders by melting the surface of irregularly shaped powders; in the present work, mechanically milled Zr powders are spheroidized by radio frequency plasma treatment and their properties are compared with those of commercial Zircaloy-2 alloy powder. Spherical Zr particles are successfully fabricated by plasma treatment, although their flowability and impurity contents are poorer than those of the commercial Zircaloy-2 alloy powder. This result shows that radio-frequency plasma treatment with mechanically milled powders requires further research and development for manufacturing low-cost powders for additive manufacturing.
        4,000원
        107.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate the basic data of Cirsium setidens Nakai fine powder (FPC), which will then be used in the development of functional fooditems. We measures and evaluated the level of pectolinarin content, phenol content, flavonoids content, antioxidants and anti-obesity properties of FPC. Our results from the study showed that the pectolinarin, phenol, and flavonoids contents of FPC measured at 10.95±0.15 mg/g, 12.92±0.18 mg gallic acid equivalent (GAE)/g and 26.47±0.77 mg rutin equivalent (RE)/g, respectively. The exhibited antioxidant activity of FPC increased significantly depending on the dosage, and additionally. FPC did not show any cytotoxicity up to the dosage level of 500 μg/mL. During adipocyte differentiation, FPC significantly inhibited ROS production and lipid accumulation, compared with the control substance. These results suggest that FPC could be considered a promising resource of natural antioxidants and could serve a variety of health-improving roles in the production of functional food ingredients.
        4,000원
        108.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study explores reducing the oxygen content of a commercial Ti-48Al-2Cr-2Nb powder to less than 400 ppm by deoxidation in the solid state (DOSS) using Ca vapor, and investigates the effect of Ca vapor on the surface chemical state. As the deoxidation temperature increases, the oxygen concentration of the Ti-48Al-2Cr-2Nb powder decreases, achieving a low value of 745 ppm at 1100oC. When the deoxidation time is increased to 2 h, the oxygen concentration decreases to 320pp m at 1100oC, and the oxygen reduction rate is approximately 78% compared to that of the raw material. The deoxidized Ti-48Al-2Cr-2nb powder maintains a spherical shape, but the surface shape changes slightly owing to the reaction of Ca and Al. The oxidation state of Ti and Al on the surface of the Ti-48Al-2Cr-2Nb powder corresponds to a mixture of TiO2 and Al2O3. As a result, the peaks of metallic Ti and Ti suboxide intensify as TiO2 and Al2O3 in the surface oxide layer are reduced by Ca vapor deposition
        4,000원
        109.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Accurate and effective powder compaction analyses are performed for brittle materials such as graphite, utilized as a solid lubricant, by using the discrete element method (DEM). The reliability of the DEM analysis is confirmed by comparing the results of graphite powder compaction analyses using the DEM particle bonding contact model and particle non-bonding contact model with those from the powder compaction experiment under the same conditions. To improve the characteristics, the parameters influencing the compaction properties of the metal-graphite mixtures are explored. The compressibility increases as the size distribution of the graphite powder increases, where the shape of the graphite particles is uniform. The improved compaction characteristics of the metal-graphite (bonding model) mixtures are further verified by the stress transmission and compressive force distribution between the top and bottom punches. It is confirmed that the application of graphite (bonding model) powders resulted in improved stress transmission and compressive force distribution of 24% and 85%, respectively.
        4,000원
        110.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to compare the quality characteristics and antioxidant activity by varying the barley sprout powder addition time, production temperature, and powder addition ratio (0, 2, 4, 6, 8%) on the prepared rice during the manufacturing process of Nurungji. When we manufactured for 2 min at 200oC, the total polyphenol and flavonoid contents were the highest in Nurungji with 4% of barley sprout powder. In this way, we measured the weight, water content, water binding capacity, soluble solids content, reducing sugar, color, hardness, sensory evaluation experiments by varying the powder content. The weight, water binding capacity, soluble solids content, reducing sugar, and hardness increased with an increasing proportion of barley sprout powder, however the water content decreased. The L value and b value decreased and the a value increased with the influence of chlorophyll pigments in barley sprout. Sensory evaluation showed that Nurungji with 4% sprout barley powder was the highest. Therefore, we judged that it is desirable to add 4% of the powder when manufacture the barley sprout powder Nurungji.
        4,000원
        111.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the antioxidant activity and quality characteristics of rice cookie with added butterbur powder in a ratio of 0, 5, 10, 15, and 20% to confirm the possibility of butterbur as a functional food. The moisture content, spread factor, leavening rate, and hardness of rice cookies increased with an increase in the amount of butterbur powder; whereas a decrease in the pH and baking loss rate was observed. The L and b values d ec reased as the amount of butterbur powder increased, but the value was the lowest when 5% of butterbur powder was added. The sensory liking score showed the highest preference for 10% butterbur powder regarding appearance, flavor, taste, texture, and overall preference. In the principal component analysis (PCA), the addition of 10% butterbur powder positively affected the measure of food acceptance in terms of organoleptic properties of butterbur. Besides, as the amount of added butterbur powder increased, the antioxidant activity of rice cookies increased. Based on these results, it appears that the addition of butterbur powder to rice cookies in a 10% ratio can produce rice cookies with excellent antioxidant activity, overall quality, and high preference.
        4,600원
        112.
        2021.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fabrication of a ferromagnetic composite powder for the magnesium and BaFe12O19 system by mechanical alloying (MA) is investigated at room temperature. Mixtures of Mg and BaFe12O19 powders with a weight ratio of Mg:BaFe12O19 = 4:1, 3:2, 2:3 and 1:4 are used. Optimal MA conditions to obtain a ferromagnetic composite with fine microstructure are investigated by X-ray diffraction, differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM) measurement. It is found that Mg-BaFe12O19 composite powders in which BaFe12O19 is dispersed in Mg matrix are successfully produced by MA of BaFe12O19 with Mg for 80 min. for all compositions. Magnetization of Mg- BaFe12O19 composite powders gradually increases with increasing the amounts of BaFe12O19, whereas coercive force of MA powders gradually decreases due to the refinement of BaFe12O19 powders with MA time for all compositions. However, it can be seen that the coercivity of Mg-BaFe12O19 MA composite powders with a weight ratio of Mg:BaFe12O19=4:1 and 3:2 for MA 80 min. are still high, with values of 1260 Oe and 1320 Oe compared to that of Mg:BaFe12O19=1:4. This clearly suggests that the refinement of BaFe12O19 powders during MA process for Mg:BaFe12O19=4:1 and 3:2 tends to be suppressed due to ductile Mg powders.
        4,000원
        113.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to effectively supplement vitamin D and increase the consumption of ear mushroom based on the investigation of the quality characteristics of cookies containing ear mushroom supplemented with vitamin D. Cookies were made of 0%, 1%, 3%, and 5% ear mushroom powder treated by ultraviolet B. Increased addition of ear mushroom powder led to a decrease in the bulk density of the dough as well as a spread factor, color value, and hardness of the cookies. There was no significant difference in the loss rate, but the water content of the dough and cookies was increased. The total polyphenol content of cookies added with 1~5% ear mushroom powder was higher than that of the 0%. The DPPH free radical scavenging activity of cookies added with 5% ear mushroom powder (23.8%) was 2 times higher than that of the 0% (10.9%). The vitamin D2 content of cookies added with 5% ear mushroom powder (835.5 μg/100 g D.W.) was 44 times higher than that of the 0% (19.0 μg/100 g D.W.). Consequently, ear mushroom powder is considered to be suitable for the production of functional cookies because of high values of antioxidant activity and vitamin D2 content.
        4,000원
        114.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to evaluate the quality characteristics of white pan bread added with wheat sprout powder without treatment (WP) and wheat sprout powder with only enzyme treatment (WPE), only lactic acid bacteria treatment (WPL) and enzyme and lactic acid bacteria treatment (WPE&L). The three different powder concentration levels of 1%, 3%, and 5% were added to flour to produce the white pan bread. The bread volume and specific volume of the WPE&L group were the highest among all the addition groups. The bread weight, a-value, and b-value of the WP group was highest among all the addition groups, but the bread baking loss and the L-value of the WP group was the lowest among all the addition groups. The texture measurements indicated that the hardness, gumminess, and chewiness values of the bread were the highest in the WP group. The sensory evaluation test showed that bread in the WPE&L group with 3% wheat sprout powder was the best among all the samples studied. Based on our findings, we suggest that the enzyme and lactic acid bacteria pretreated wheat sprout powder is an effective ingredient for improving the overall quality of white pan bread.
        4,800원
        115.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A well-established characterization method is required in powder bed fusion (PBF) metal additive manufacturing, where metal powder is used. The characterization methods from the traditional powder metallurgy process are still being used. However, it is necessary to develop advanced methods of property evaluation with the advances in additive manufacturing technology. In this article, the characterization methods of powders for metal PBF are reviewed, and the recent research trends are introduced. Standardization status and specifications for metal powder for the PBF process which published by the ISO, ASTM, and MPIF are also covered. The establishment of powder characterization methods are expected to contribute to the metal powder industry and the advancement of additive manufacturing technology through the creation of related databases.
        4,200원
        116.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 천연 기능성 소재인 비파잎의 첨가가 흑염소고기 저지방 소시지의 품질특성 및 항산화 활성에 미치는 영향을 알아보기 위하여 실시하였다. 20% 지방을 첨가한 대조구(control), 10% 지방을 첨가한 처리구(LF), 10% 지방과 0.25% 비파잎분말을 첨가한 처리구(LL)로 처리하였다. 저지방 소시지인 LF, LL은 대조구보다 지방함량은 낮고, 수분과 단백질 함량은 높았고, 보수력도 향상되었다(p<0.05). 육색의 경우 비파잎을 첨가한 LL은 적색도와 황색도가 감소하였고(p<0.05), TPA에서 탄력성, 검성, 씹힘성 및 응집성은 LF보다 증가하였고, 대조구와 유사한 조직감을 갖는 것으로 나타났다(p<0.05). TBARS와 DPPH radical 소거능은 비파잎을 첨가한 LL에서 우수한 항산화 활성을 나타냈다. 따라서 기능성 소재인 비파잎을 첨가한 흑염소고기 저지방 소시지는 고단백, 저지방 특성의 흑염소고기 섭취 기회를 늘려줌과 동시에 건강 지향적 육제품 개발의 기초자료로 활용될 수 있다.
        4,000원
        117.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the substitution effect of phosphate and isolated soybean powder (ISP) by Allomyrina dichotoma larvae powder (AP) in emulsion sausage. The sausages were prepared for five treatments: 1) positive control (PC): sausages manufactured with sodium pyrophosphate (0.3%) and ISP (1%); 2) negative control (NC): sausages manufactured without sodium pyrophosphate, and ISP; 3) phosphate replacement (PR): sausages manufactured with ISP and AP (1%); 4) ISP replacement (IR): sausages manufactured with sodium pyrophosphate and AP; 5) phosphate and ISP replacement (PIR): sausages manufactured with AP. The 1% AP extract showed DPPH radical scavenging (45.65±2.468%) and metal chelating (22.46±3.559%) activity. The high pH value of AP (8.03) increased the pH of the meat batter of PR, IR, and PIR (p<0.05), but there was no inhibitory effect on cooking loss. Cooking loss of IR was not significantly different with PC due to phosphate. The addition of AP decreased the L* and a* values and increased the b* values, and decreased hardness, chewiness, and springiness of PR, IR, and PIR (p<0.05). AP did not inhibit lipid oxidation in sausages, in contrast to phosphate. In sensory evaluation, the addition of AP resulted in low scores for all sensory parameters of the sausages, although most panels had normal or positive awareness (p<0.05). Aroma was more influential on samples than color. Overall, AP did not replace phosphate and ISP in the sausages. Therefore, processes such as eliminating unique aroma and color and increasing solubility through particle size control are necessary to use AP as a protein source.
        4,200원
        118.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the antioxidative activity of Jeolpyun containing S. glauca (Bunge) Bunge powder (2%, 4%, 6%, and 8%) and extract (2%, 4%, 6%, and 8%) was evaluated based on the total polyphenol contents, electron-donating ability, scavenging of superoxide anion radical, and decomposition of hydrogen peroxide. Total polyphenol contents of Jeolpyun containing 8% S. glauca (Bunge) Bunge powder were the highest with a value of 2,280±0.00 μg GAE/mL. It was observed that total polyphenol content exhibited a significant relation with concentrations at p<0.05. The electron-donating ability of Jeolpyun containing 8% S. glauca (Bunge) Bunge extract was the highest with a value of 83.93±0.69%. The electron-donating abilities revealed significant differences between concentrations (p<0.05). The superoxide radical scavenging ability of the blank was 0.01523±0.00068 and Jeolpyun containing 6% S. glauca (Bunge) Bunge powder was the highest with a value of 0.00977±0.00842. The hydrogen peroxide decomposing ability of Jeolpyun containing 0% S. glauca (Bunge) Bunge powder was -0.00377±0.0049; 8% S. glauca (Bunge) Bunge powder revealed the highest decomposing ability of -0.0476±0.0234. Hydrogen peroxide decomposing abilities revealed significant differences between concentrations (p<0.05). Jeolpyun containing S. glauca (Bunge) Bunge powder and extract demonstrated improved antioxidative activities.
        4,000원
        119.
        2020.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Used in the ceramic tile market as a representative building material, relief ceramic tile is showing increased demand recently. Since ceramic tiles are manufactured through a sintering process at over 1,000 oC after uniaxial compression molding by loading granule powders into a mold, it is very important to secure the flowability of granular powders in a mold having a relief pattern. In this study, kaolin, silica, and feldspar are used as starting materials to prepare granule powders by a spray dryer process; the surface of the granule powders is subject to hydrophobic treatment with various concentrations of stearic acid. The effect on the flowability of the granular powder according to the change of stearic acid concentration is confirmed by measuring the angle of repose, tap density, and compressibility, and the occurrence of cracks in the green body produced in the mold with the relief pattern is observed. Then, the green body is sintered by a fast firing process, and the water absorption, flexural strength, and durability are evaluated. The surface treatment of the granule powders with stearic acid improves the flowability of the granule powders, leading to a dense microstructure of the sintered body. Finally, the hydrophobic treatment of the granule powders makes it possible to manufacture relief ceramic tiles having a flexural strength of 292 N/cm, a water absorption of 0.91 %, and excellent mechanical durability
        4,000원
        120.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to evaluate the physicochemical components and antioxidant activities of wheat sprout powder prepared by the enzymatic hydrolysis and lactic acid bacteria treatment. The four kinds of pre-treatment were: no treatment (WP), treated with enzyme (WPE), treated with lactic acid bacteria (WPL), and treated with enzyme and lactic acid bacteria (WPEL) were applied to the wheat sprout powder. The WPEL had higher total free amino acid and essential amino acid content than the other samples. As for the volatile aroma of the wheat sprout powder, 29 types of compounds were identified in the WP and WPL, 28 types in the WPE, and 27 types in the WPEL, respectively. The total polyphenols and flavonoids contents, in the wheat sprout powder was enhanced with the enzyme and the lactic acid bacteria pre-treatment. The WPEL had highest DPPH radical scavenging activities. The overall acceptability was the highest at 6.24 points in the WPEL. Based on these observations, it was confirmed that the enzyme and lactic acid bacteria pre-treatment could improve the antioxidant activities and active component of the wheat sprout powder.
        4,600원