검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 1,826

        325.
        2017.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        An optimum route to fabricate a hybrid-structured W powder composed of nano and micro size powders was investigated. The mixture of nano and micro W powders was prepared by a ball milling and hydrogen reduction process for WO3 and W powders. Microstructural observation for the ball-milled powder mixtures revealed that the nano-sized WO3 particles were homogeneously distributed on the surface of large W powders. The reduction behavior of WO3 powder was analyzed by a temperature programmed reduction method with different heating rates in Ar-10% H2 atmosphere. The activation energies for the reduction of WO3, estimated by the slope of the Kissinger plot from the amount of reaction peak shift with heating rates, were measured as 117.4 kJ/mol and 94.6 kJ/mol depending on reduction steps from WO3 to WO2 and from WO2 to W, respectively. SEM and XRD analysis for the hydrogen-reduced powder mixture showed that the nano-sized W particles were well distributed on the surface of the micro-sized W powders.
        4,000원
        326.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A Nanosized WO3 and CuO powder mixture is prepared using novel high-energy ball milling in a bead mill to obtain a W-Cu nanocomposite powder, and the effect of milling time on the structural characteristics of WO3-CuO powder mixtures is investigated. The results show that the ball-milled WO3-CuO powder mixture reaches at steady state after 10 h milling, characterized by the uniform and narrow particle size distribution with primary crystalline sizes below 50 nm, a specific surface area of 37 m2/g, and powder mean particle size (D50) of 0.57 μm. The WO3-CuO powder mixtures milled for 10 h are heat-treated at different temperatures in H2 atmosphere to produce W-Cu powder. The XRD results shows that both the WO3 and CuO phases can be reduced to W and Cu phases at temperatures over 700oC. The reduced W-Cu nanocomposite powder exhibits excellent sinterability, and the ultrafine W-Cu composite can be obtained by the Cu liquid phase sintering process.
        4,000원
        327.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Solder paste is widely used as a conductive adhesive in the electronics industry. In this paper, nano and microsized mixed lead-free solder powder (Sn-Ag-Cu) is used to manufacture solder paste. The purpose of this paper is to improve the storage stability using different types of solvents that are used in fabricating the solder paste. If a solvent of sole acetate is used, the nano sized solder powder and organic acid react and form a Sn-Ag-Cu malonate. These formed malonates create fatty acid soaps. The fatty acid soaps absorb the solvents and while the viscosity of the solder paste rises, the storage stability and reliability decrease. When ethylene glycol, a dihydric alcohol, is used the fatty acid soaps and ethylene glycol react, preventing the further creation of the fatty acid soaps. The prevention of gelation results in an improvement in the solder paste storage ability.
        4,000원
        328.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effect of the mixing method on the characteristics of hybrid-structure W powder with nano and micro sizes is investigated. Fine WO3 powders with sizes of ~0.6 μm, prepared by ball milling for 10 h, are mixed with pure W powder with sizes of 12 μm by various mixing process. In the case of simple mixing with ball-milled WO3 and micro sized W powders, WO3 particles are locally present in the form of agglomerates in the surface of large W powders, but in the case of ball milling, a relatively uniform distribution of WO3 particles is exhibited. The microstructural observation reveals that the ball milled WO3 powder, heat-treated at 750oC for 1 h in a hydrogen atmosphere, is fine W particles of ~200 nm or less. The powder mixture prepared by simple mixing and hydrogen reduction exhibits the formation of coarse W particles with agglomeration of the micro sized W powder on the surface. Conversely, in the powder mixture fabricated by ball milling and hydrogen reduction, a uniform distribution of fine W particles forming nano-micro sized hybrid structure is observed.
        4,000원
        329.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We examined the quality characteristics of pound cake with prepared Aronia melanocarpa powder, which included the physical characteristics, antioxidant activity and sensory evaluation in this study. Pound cakes were prepared with various ratios of Aronia powder (0, 5, 10, 15, 20%). No significant difference in loss rate or weight was found from increased Aronia powder concentration. The color of pound cake was darker and reddish with the addition of Aronia powder. Lightness (L) and yellowness (b) significantly decreased with the addition of Aronia powder, whereas redness (a) increased (p<0.05). the qualities of hardness, cohesiveness, gumminess and chewiness of the pound cake prepared with the addition of Aronia powder were significantly increased when compared to control(p<0.05), with exception of 20% addtion. Total phenolic contents and DPPH radical scavenging activity was significantly elevated by the addition of Aronia powder(p<0.05). The pound cake with 10% Aronia powder showed the strongest positive sensory properties with regard to taste and overall palatibility. These results suggest that the addition of 10 % Aronia to pound cake batter could well serve to improve the overall quality, texture and taste of the final product.
        4,000원
        330.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to improve the usability of mealworm and the nutritional quality of acorn Mook mostly composed of carbohydrates, we prepared acorn Mook using with different levels of mealworm powder, and the physico-chemical and sensory evaluation were investigated. In the content of proximate chemical composition, moisture content did not show any significant difference. But crude protein, crude ash, and crude fat contents were increased with increasing mealworm content. Carbohydrate content was reduced as mealworm content increased. Lightness showed no significant difference among treatments, redness was increased, and yellowness was decreased as the amount of mealworm powder increased. In physiological properties, hardness, gumminess, chewiness, and springiness were significantly increased as the amount of mealworm powder decreased. However, adhesiveness and cohesiveness were not significantly different. Ascorbic acid content, activities of DPPH and ABTS radical scavenging activities were decreased with increasing amount of mealworm in acorn Mook. In sensory evaluation, acorn Mook containing 0.75% of mealworm powder showed highly preference compared with the control.
        4,000원
        331.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate the body fat-lowering effect of garlic powder in peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α)-luciferase transgenic mice (TG). In this study, we generated transgenic mice with a PGC-1α promoter (—970/+412 bp) containing luciferase as a reporter gene. Mice were fed a 45% high-fat diet for 8 weeks to induce obesity. Subsequently, mice were maintained on either a high-fat control diet (CON), or high-fat diets supplemented with 2% (GP2) or 5% (GP5) garlic powder for an additional 8 weeks. Dietary garlic powder reduced the body weight in the GP2 and GP5 groups, compared to the CON group. Furthermore, garlic supplementation significantly decreased the plasma levels of triglycerides, total cholesterol, and leptin in the GP5 group, compared to the CON group. Specifically, luciferase activity in liver, white adipose tissue (WAT), and brown adipose tissue (BAT) was increased by garlic supplementation in a dose-dependent manner. These results suggest that the body fat-lowering effect of garlic powder might be related to PGC-1α by the increase in luciferase activity in liver, WAT, and BAT. Furthermore, transgenic mice might be useful for evaluating the body fat-lowering effect of various health functional foods.
        4,000원
        332.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the quality characteristics and antioxidant activities of salad dressing prepared with acaiberry powder (0, 1, 3, and 5%). The pH and titratable acidity increased as the acaiberry powder increased. The sugar content showed no significant differences between samples. The viscosity was lowest in the controls and increased with increasing amounts of the acaiberry powder. The lightness and yellowness values decreased, while the redness values increased with increasing amounts of acaiberry powder. The total polyphenol content ranged from 10.26-45.19 mg GAE/100 g, increasing with increased acaiberry powder levels. The antioxidant activities measured via DPPH radical scavenging activity, reducing power and FRAP also increased with increasing acaiberry powder concentrations. Finally, a consumer acceptance test revealed that up to 3% acaiberry powder could be added to salad dressing to provide high antioxidant activity without sacrificing sensory quality.
        4,000원
        333.
        2017.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        An optimum route to fabricate oxide dispersion strengthened ferritic superalloy with desired microstructure was investigated. Two methods of high energy ball milling or polymeric additive solution route for developing a uniform dispersion of Y2O3 particles in Fe-Cr-Al-Ti alloy powders were compared on the basis of the resulting microstructures. Microstructural observation revealed that the crystalline size of Fe decreased with increases in milling time, to values of about 15-20 nm, and that an FeCr alloy phase was formed. SEM and TEM analyses of the alloy powders fabricated by solution route using yttrium nitrate and polyvinyl alcohol showed that the nano-sized Y-oxide particles were well distributed in the Fe based alloy powders. The prepared powders were sintered at 1000 and 1100 oC for 30 min in vacuum. The sintered specimen with heat treatment before spark plasma sintering at 1100 oC showed a more homogeneous microstructure. In the case of sintering at 1100 oC, the alloys exhibited densified microstructure and the formation of large reaction phases due to oxidation of Al.
        4,000원
        334.
        2017.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnS powder was synthesized using a relatively facile and convenient glycothermal method at various reaction temperatures. ZnS was successfully synthesized at temperatures as low as 125 oC using zinc acetate and thiourea as raw materials, and diethylene glycol as the solvent. No mineralizers or precipitation processes were used in the fabrication, which suggests that the spherical ZnS powders were directly prepared in the glycothermal method. The phase composition, morphology, and optical properties of the prepared ZnS powders were characterized using XRD, FE-SEM, and UV-vis measurements. The prepared ZnS powders had a zinc blende structure and showed average primary particles with diameters of approximately 20~30 nm, calculated from the XRD peak width. All of the powders consisted of aggregated secondary powders with spherical morphology and a size of approximately 0.1~0.5 μm; these powders contained many small primary nanopowders. The as-prepared ZnS exhibited strong photo absorption in the UV region, and a red-shift in the optical absorption spectra due to the improvement in powder size and crystallinity with increasing reaction temperature. The effects of the reaction temperature on the photocatalytic properties of the ZnS powders were investigated. The photocatalytic properties of the assynthesized ZnS powders were evaluated according to the removal degree of methyl orange (MO) under UV irradiation (λ = 365 nm). It was found that the ZnS powder prepared at above 175 oC exhibited the highest photocatalytic degradation, with nearly 95 % of MO decomposed through the mediation of photo-generated hydroxyl radicals after irradiation for 60 min. These results suggest that the ZnS powders could potentially be applicable as photocatalysts for the efficient degradation of organic pollutants.
        4,000원
        335.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Most of the red ginseng (RG) products contain active substances derived from hot water or alcohol extraction. Since active substances of RG are divided into two two types: water-soluble and liposoluble, water or alcohol is needed as an extraction solvent and this leads the different extraction yields and components of the active substances. To overcome the limit, whole red ginseng powder can be used and consumed by consumers. In this study, the physicochemical properties and extractable active substance contents of variable-sized RG powder (158.00 μm, 8.45 μm, and 6.33 μm) were analyzed, and dispersion stability was measured to investigate the suitable size of RG powder for industrial processing. In the results, no significant difference was found from the changes in color intensity and thiobarbutric acid tests at 4°C, 25°C, and 40°C for 4 weeks. There was no significant difference on the production of antioxidants and ginsenoside among the samples (p>0.05). In dispersion stability, RG-158.00 μm was precipitated immediately, and the dispersion stabilities between RG-8.45 μm and RG-6.33 μm showed no significant difference. It implies that fine RG is suitable for the production process. With further study, it seemed that the physicochemical effects of RG particle sizes can be clearly revealed.
        4,000원
        336.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanopowders provide better details for micro features and surface finish in powder injection molding processes. However, the small size of such powders induces processing challenges, such as low solid loading, high feedstock viscosity, difficulty in debinding, and distinctive sintering behavior. Therefore, the optimization of process conditions for nanopowder injection molding is essential, and it should be carefully performed. In this study, the powder injection molding process for Fe nanopowder has been optimized. The feedstock has been formulated using commercially available Fe nanopowder and a wax-based binder system. The optimal solid loading has been determined from the critical solid loading, measured by a torque rheometer. The homogeneously mixed feedstock is injected as a cylindrical green body, and solvent and thermal debinding conditions are determined by observing the weight change of the sample. The influence of the sintering temperature and holding time on the density has also been investigated. Thereafter, the Vickers hardness and grain size of the sintered samples have been measured to optimize the sintering conditions.
        4,000원
        337.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This purpose of this study was to investigate cooking characteristics of noodles prepared by adding 0, 2, 4 or 6 percent of Capsosiphon fulvescens to wheat flour containing konjac powder. Water binding capacity was significantly increased with increasing amounts of Capsosiphon fulvescens. Weight and volume of cooked noodles increased significantly in proportion with the amount of Capsosiphon fulvescens. Turbidity of the soup after cooking also increased with the addition of Capsosiphon fulvescens. Brightness(L) and redness(a) were decreased with addition of Capsosiphon fulvescens. Yellowness( b) increased. The color value of cooked noodles was decreased compared with that of wet noodles. Sensory evaluation scores revealed that cooked noodles with 4 percent addition group were highest in terms of color, flavor and overall acceptability. This study validates that addition of Amorphophallus konjac and 4 percent Capsosiphon fulvescens may improve functionality and preference of noodles.
        4,000원
        338.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of Goami 2 on the properties of Garaetteok. The moisture, crude protein, crude lipid and crude ash contents of the rice were 16.02, 5.40, 1.87 and 0.77%, respectively. The amylose contents (32.16%) and total dietary fiber contents (9.03%) were the highest in Goami 2. The water binding capacity of Goami 2 (167.84%) was higher than general rice flour. Using a rapid visco analyzer (RVA), the initial pasting temperature of Goami 2 was found to be the highest; also, the peak viscosities of Goami 2 were higher than general rice powder. To assess the effect of Goami 2 on the quality characteristics of Garaetteok, the rice-cake was made by adding various amounts of Goami 2 (0, 10, 20, 30, and 40% w/w) to rice. It was observed that higher the amount of added Goami 2, lower were the grades. In terms of the color values of Goami 2 addition, the L-values of Garaetteok were lower with increasing amount of Goami 2; addition of 40% Goami 2 had the lowest value. The textural properties (hardness) also showed that tteok containing the greater amounts of Goami 2 were considerably harder compared with the control. Sensory preference tests revealed that addition of less Goami 2 had the highest scores for appearance, color and overall acceptability, and the Goami 2 added was lower than control. Therefore, as compared to others cultivars, rice flour proved the most acceptable for the preparation of Garaetteok with cultivar rice.
        4,000원
        339.
        2017.08 KCI 등재 구독 인증기관·개인회원 무료
        This study added stevia leaf powder at ratios of 0.5, 1.0, 1.5, and 2.0 percent to Omija-pyun (Schisandra chinensis Jelly) as a natural low-calorie sweetener instead of sugar which is added to Omija-pyun in considerable amounts to evaluate quality characteristics and antioxidant activities compared to the control group with the addition of sugar. Moisture content of Omija-pyun expanded by increasing the measurement of stevia leaf powder (p<0.001), pH (p<0.01) and sugar content (p<0.001) decreased. L-values and b-values revealed a tendency to increase by adding more stevia leaf powder, but a-value revealed a tendency to decrease (p<0.001). Hardness (p<0.001) and chewiness (p<0.05) decreased by adding more stevia leaf powder. Based on the consumer preference evaluation, Omija-pyun with the addition of 0.5 percent stevia leaf powder was the most preferable in terms of color and flavor (p<0.001). The control group and Omija-pyun with the addition of 0.5 percent stevia leaf powder was the most preferable in terms of taste and texture (p<0.001). There were significant differences in the organoleptic properties except hardness between the samples by quantitative descriptive analysis. The control group revealed the highest preference in terms of redness and transparency, and redness and transparency tended to decrease by adding more stevia leaf powder (p<0.001). Organoleptic properties on bitterness and sourness were enhanced by adding more stevia leaf powder in the principal component analysis (PCA). Regarding antioxidant properties, total phenol compounds and flavonoid contents of Omija-pyun increased by adding more stevia leaf powder, and DPPH radical scavenging capacity also increased (p<0.001). Based on results, it is preferable to serve Omija-pyun with the addition of 1.0 percent stevia leaf powder instead of sugar within the context of quality and antioxidant activity.
        340.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe3O4/Fe/graphene nanocomposite powder is synthesized by electrical wire explosion of Fe wire and dispersed graphene in deionized water at room temperature. The structural and electrochemical characteristics of the powder are characterized by the field-emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, field-emission transmission electron microscopy, cyclic voltammetry, and galvanometric discharge-charge method. For comparison, Fe3O4/Fe nanocomposites are fabricated under the same conditions. The Fe3O4/Fe nanocomposite particles, around 15-30 nm in size, are highly encapsulated in a graphene matrix. The Fe3O4/Fe/graphene nanocomposite powder exhibits a high initial charge specific capacity of 878 mA/g and a high capacity retention of 91% (798 mA/g) after 50 cycles. The good electrochemical performance of the Fe3O4/Fe/graphene nanocomposite powder is clearly established by comparison of the results with those obtained for Fe3O4/Fe nanocomposite powder and is attributed to alleviation of volume change, good distribution of electrode active materials, and improved electrical conductivity upon the addition of graphene.
        4,000원