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        검색결과 2,191

        461.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        수확과정에서 버려지고 있는 고구마 잎을 이용한 기능성 식품소재로서 활용가능성을 검토하고자, 밀가루 중량 대비 고구마 잎 분말을 2, 3, 5, 7%의 비율로 첨가하여 식빵을 제조 하고, 반죽 및 제빵 특성, 생리활성 및 기능성분 등을 조사하 였다. 반죽의 수분흡수량은 7% 첨가 시 가장 높았고, 반죽시 간은 유의적인 차이를 보이지 않았으며, 반죽의 저항도는 2~3% 첨가할 때가 가장 안정적이었다. 식빵의 수분 함량은 첨가량이 증가하여도 큰 차이를 보이지 않았고, 식빵의 내부색은 첨가량이 증가할수록 L값과 a값은 감소하였으나, b값은 증가하였다. 식빵의 부피와 비용적 및 굽기 손실률은 첨가량 이 증가할수록 감소하였으나, 항산화 활성과 총 폴리페놀, 루 테인 및 베타카로틴 함량은 증가하였다. 관능평가의 결과, 고 구마 잎 분말의 2~3% 첨가 시 맛과 색깔, 조직감, 입안에서의 씹힘성과 종합적인 기호도에서 가장 우수한 값을 얻었다. 이 상의 결과에서 고구마 잎 분말의 2~3% 첨가 시, 제빵 적성과 기능성, 상품성이 우수한 식빵을 제조할 수 있었다.
        4,000원
        462.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To develop and industrialize functional foods containing peanut sprout extract (PSE) and powder (PSP), the present study investigated the quality characteristics and antioxidant effects of breads prepared with 0, 0.5, 1, 2, 2.5, 5, 7.5, and 10% PSE and PSP. The expansion ratio of the dough, the quality characteristics such as volume, weight, specific volume, baking loss, color, texture, and sensory preference were evaluated. There were significant differences in the bread volume and specific volume among the control, PSE and PSP groups (p<0.001). Additionally, the weight and baking loss were decreased with an increasing amount of PSP (p<0.001). As the amount of PSE and PSP were increased, the L value of the crumb decreased, whereas the a and b values of the crumb significantly increased (p<0.001), suggesting that the crumb color of the bread may be significancy (p<0.001). As the amount of PSE and PSP increased, the hardness of bread significantly and rapidly increased from 5%. Meanwhile, there was no significance in springiness among the control, PSE and PSP groups. The total resveratrol content and DPPH free radical-scavenging activity of the bread significantly increased depending on the amounts of PSE and PSP (p<0.001). In the overall acceptance test, no significant differences were observed in the color, flavour, or texture, however, the taste and overall acceptance were significantly decreased between the control and the PSE group. All the sensory characteristics in the PSP group were significantly reduced compared with the control. Considering the above results, it can be expected that the suitable amount of PSE and PSP substituted for wheat flour will be from 1.0 to 2.5%. Furthermore, follow-up studies are being carried out continuously.
        4,500원
        463.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two sintering methods of a pressureless sintering and a spark-plasma sintering are tested to densify the Fe-TiC composite powders which are fabricated by high-energy ball-milling. A powder mixture of Fe and TiC is prepared in a planetary ball mill at a rotation speed of 500 rpm for 1h. Pressureless sintering is performed at 1100, 1200 and 1300oC for 1-3 hours in a tube furnace under flowing argon gas atmosphere. Spark-plasma sintering is carried out under the following condition: sintering temperature of 1050oC, soaking time of 10 min, sintering pressure of 50 MPa, heating rate of 50oC, and in a vacuum of 0.1 Pa. The curves of shrinkage and its derivative (shrinkage rate) are obtained from the data stored automatically during sintering process. The densification behaviors are investigated from the observation of fracture surface and cross-section of the sintered compacts. The pressureless-sintered powder compacts show incomplete densification with a relative denstiy of 86.1% after sintering at 1300oC for 3h. Spark-plasma sintering at 1050oC for 10 min exhibits nearly complete densification of 98.6% relative density under the sintering pressure of 50 MPa.
        4,000원
        464.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The GaN-powder scrap generated in the manufacturing process of LED contains significant amounts of gallium. This waste can be an important resource for gallium through recycling of scraps. In the present study, the influence of annealing temperatures on the structural properties of GaN powder was investigated when the waste was recycled through the mechanochemical oxidation process. The annealing temperature varied from 200oC to 1100oC and the changes in crystal structure and microstructure were studied. The annealed powder was characterized using various analytical tools such as TGA, XRD, SEM, and XRF. The results indicate that GaN structure was fully changed to Ga2O3 structure when annealed above 900oC for 2 h. And, as the annealing temperature increased, crystallinity and particle size were enhanced. The increase in particle size of gallium oxide was possibly promoted by powder-sintering which merged particles to larger than 50 nm.
        4,000원
        465.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The synthesis of NiTi alloy powders by hydrogen reduction and dehydrogenation process of NiO and TiH2 powder mixtures is investigated. Mixtures of NiO and TiH2 powders are prepared by simple mixing for 1 h or ball milling for 24 h. Simple-mixed mixture shows that fine NiO particles are homogeneously coated on the surface of TiH2 powders, whereas ball milled one exhibits the morphology with mixing of fine NiO and TiH2 particles. Thermogravimetric analysis in hydrogen atmosphere reveals that the NiO and TiH2 phase are changed to metallic Ni and Ti in the temperature range of 260 to 290oC and 553 to 639oC, respectively. In the simple-mixed powders by heat-up to 700oC, agglomerates with solid particles and solidified liquid phase are observed, and the size of agglomerates is increased at 1000oC. From the XRD analysis, the presence of liquid phase is explained by the formation and melting of NiTi2 intermetallic compound due to an exothermic reaction between Ni and Ti. The simple-mixed powders, heated to 1000oC, lead to the formation of NiTi phase but additional Ni-, Ti-rich and Ti-oxide phases. In contrast, the microstructure of ball-milled powders is characterized by the neck-grown particles, forming Ni3Ti, Ti-oxide and unreacted Ni phase.
        4,000원
        466.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Spherical fine cobalt powders were fabricated by new liquid reduction method. Commercial cobalt sufate heptahydrate was used as raw material. Also ethylene glycol was used as solvent and hydrazine-sodium hypophosphite mixture was used as reduction agent for the new liquid reduction method. A plate shaped cobalt powders with an approximately 300 nm were prepared by a traditional wet ruduction method using distilled water as solvent and hydrazine. Spherical fine cobalt powders with an average size of 1-3 μm were synthesized by a new liquid reduction method in 0.3M cobalt sulfate and 1.5M hydrazine-0.6M sodium hypophosphite mixture at 333K.
        4,000원
        467.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bi2Te3 related compounds show the best thermoelectric properties at room temperature. However, n-type Bi2Te2.7Se0.3 showed no improvement on ZT values. To improve the thermolectric propterties of n-type Bi2Te2.7Se0.3, this research has Cu-doped n-type powder. This study focused on effects of Cu-doping method on the thermoelectric properties of n-type materials, and evaluated the comparison between the Cu chemical and mechanical doping. The synthesized powder was manufactured by the spark plasma sintering(SPS). The thermoelectric properties of the sintered body were evaluated by measuring their Seebeck coefficient, electrical resistivity, thermal conductivity, and hall coefficient. An introduction of a small amount of Cu reduced the thermal conductivity and improved the electrical properties with Seebeck coefficient. The authors provided the optimal concentration of Cu0.1Bi1.99Se0.3Te2.7. A figure of merit (ZT) value of 1.22 was obtained for Cu0.1Bi1.9Se0.3Te2.7 at 373K by Cu chemical doping, which was obviously higher than those of Cu0.1Bi1.9Se0.3Te2.7 at 373K by Cu mechanical doping (ZT=0.56) and Cu-free Bi2Se0.3Te2.7 (ZT=0.51).
        4,000원
        468.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Anodic aluminum oxide (AAO) has been widely used for the development and fabrication of nano-powder with various morphologies such as particle, wire, rod, and tube. So far, many researchers have reported about shape control and fabrication of AAO films. However, they have reported on the shape control with different diameter and length of anodic aluminum oxide mainly. We present a combined mild-hard (or hard-mild) anodization to prepare shape-controlled AAO films. Two main parameters which are combination mild-hard (or hard-mild) anodization and run-time of voltage control are applied in this work. The voltages of mild and hard anodization are respectively 40 and 80 V. Anodization was conducted on the aluminum sheet in 0.3 mole oxalic acid at 4oC. AAO films with morphologies of varying interpore distance, branch-shaped pore, diameter-modulated pore and long funnel-shaped pore were fabricated. Those shapes will be able to apply to fabricate novel nano-materials with potential application which is especially a support to prevent volume expansion of inserted active materials, such as metal silicon or tin powder, in lithium ion battery. The silicon powder electrode using an AAO as a support shows outstanding cycle performance as 1003 mAh/g up to 200 cycles.
        4,000원
        469.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electronic products are a major part of evolving industry and human life style; however most of them are known to emit electromagnetic waves that have severe health hazards. Therefore, different materials and fabrication techniques are understudy to control or limit transfer of such waves to human body. In this study, nanocomposite powder is dispersed into epoxy resin and shielding effects such as absorption, reflection, penetration and multiple reflections are investigated. In addition, nano size powder (Ni, Fe2O3, Fe-85Ni, C-Ni) is fabricated by pulsed wire evaporation method and dispersed manually into epoxy. Characterization techniques such as X-ray diffraction, Scanning electron microscopy and Transmission electron microscopy are used to investigate the phase analysis, size and shape as well as dispersion trend of a nano powder on epoxy matrix. Shielding effect is measured by standard test method to investigate the electromagnetic shielding effectiveness of planar materials, ASTM D4935. At lower frequency, sample consisting nano-powder of Fe-85%Wt Ni shows better electromagnetic shielding effect compared to only epoxy, only Ni, Fe2O3 and C-Ni samples.
        4,000원
        471.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the quality characteristics and antioxidant activities of wet noodles as well as their cooking properties following the addition of peanut sprout extract (PSE) and powder (PSP), which are known to contain a significant level of resveratrol. Wet noodles were prepared with 0, 2.5, 5, 7.5 and 10% PSE and PSP. Quality characteristics such as increasing volume of noodle, water ratio, turbidity of cooking water and color, texture, and sensory evaluation were then assessed. Additionally, the total resveratrol content in the cooked noodles was analyzed by HPLC and DPPH free radical scavenging capacity. As the amount of PSE and PSP increased, the L value of wet and cooked noodles significantly decreased, whereas the a and b values increased (p<0.001). The L value of cooked noodles was significantly lower compared to wet noodles (p<0.001) whereas the a and b values were higher. For the cutting intensity properties of the cooked noodles, hardness was reduced with increasing amounts of PSE (p<0.001), and was significantly increased in proportion to the amount of PSP (p<0.05). Meanwhile, springiness was not significantly different in all groups. Total resveratrol content and free radical scavenging activity significantly increased in proportion to the amounts of PSE and PSP (p<0.001), especially in noodles containing 5%, 7.5% and 10% PSE and PSP. Finally, sensory evaluation of PSE noodle revealed that color, flavour, taste were significantly decreased (p<0.05). But there was no difference in overall acceptance among cooked noodles with 2.5% to 5% PSE comparison to the control. Sensory characteristics in the PSP noodle showed similar results. In conclusion, these findings suggest that peanut sprout extract and powder could be potentially used as functional food ingredients. In addition, up to 5% PSE and PSP can be substituted for wheat flour.
        4,000원
        472.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 동결 건조한 모시잎 분말을 돈육패티에 첨가하여, 이들 제품에 미치는 품질특성을 평가하고자 하였다. 모시잎 분말의 일반성분은 수분 함량 4.67%(w/w), 조단백질 25.61%(w/w), 조지방 6.665%(w/w), 조회분 16.88%(w/w)로 나타났다. 모시잎 분말을 첨가한 돈육패티의 수분 함량은 분말의 첨가량이 증가될수록 감소하는 경향을 보였다. pH는 6.06~6.18로 유의적 차이를 보이지 않았다. 색도는 생육 패티에서 모시잎 분말의 첨가량이 증가할수록 명도와 적색도는 유의적(p<0.001)으로 감소하고, 황색도는 유의적(p<0.001)으로 증가하였으며, 가열육 패티에서 모시잎 분말의 첨가량이 증가할수록 명도(p<0.001)와 적색도는 감소하고, 황색도는 0.75%(w/w) 첨가군에서 가장 높은 값을 보였다(p<0.05). 물성 특성은 모시잎 분말의 첨가량이 증가할수록 경도, 탄력성, 응집성, 씹힘성에서 유의적으로 증가하였다. 지질산패도(TBARS)는 저장 기간의 경과에 따라 측정 값들이 증가하였으며, 모시잎 분말의 첨가량이 증가할수록 유의적(p<0.001)으로 낮은 TBARS 값을 보여 지질산패에 효과적으로 나타났다. 관능적 특성으로 색감에서는 모시잎 분말의 첨가량이 증가함에 따라 유의적(p<0.05)인 경향을 보였으며, 전반적인 기호도에서는 모시잎 분말 0.5%(w/w) 첨가군에서 유의적(p<0.01)인 경향을 보이며 가장 높은 기호도를 나타내었다. 본 연구를 통해 돈육패티 제조 시 모시잎 분말을 0.5%(w/w) 정도 첨가하는 것이 바람직한 것으로 사료되며, 돈육패티에 모시잎 분말을 첨가함에 따라 돈육 특유의 이취를 감소시키며, 색상과 맛 등의 기호도를 향상시켜 관능적 품질을 향상시킬 수 있을 것으로 보이며, 관능적 평가뿐만 아니라, 저장 중 지방산패를 억제할 수 있을 것으로 보인다.
        4,000원
        473.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of substituting whey protein concentrate (WPC) powder for rice flour in the preparation of seolgiddeok were determined by objective and subjective tests. Milk whey is drained from milk curd as a by-product of the cheese manufactureing process. Whey protein is known as a good nutritional source and is a functional material for many processed foods. WPC contains more than 80% whey protein. The moisture content decreased gradually during storage and the decrease in moisture was less in the control than in the WPC powder substituted groups. The color lightness (L) decreased significantly as the amount of WPC powder increased, wherease redness (a) and yellowness (b) both increased. Texture analyses revealed that the hardness, chewiness, gumminess and adhesiveness of seolgiddeok tended to increase in proportion to the amount of WPC powder in the formula. Seolgiddeok gelatinization was investigated by amylographing. Initial pasting temperature, peak viscosity, hot pasting viscosity and breakdown were low in seolgiddeok prepared with WPC powder substituted for rice flour. Setback had the lowest value in the control. Sensory evaluations revealed that, seolgiddeok prepared with 3% WPC powder had the highest overall acceptability score. These results indicated that WPC seolgiddeok with 3% WPC powder has the best quality.
        4,000원
        474.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to verify the effects of Erigeron annuus powder on serum lipid levels of high-fat diet-induced mice from a nutritional viewpoint. Erigeron annuus powder has been used as a folk remedy since ancient times in Korea. There was no significant difference in the weight of the kidneys and spleens of the mice. The high-fat diet group had a significantly higher kidney weight compared to other groups (p<0.05). In the group of mice fed 20% Erigeron annuus powder with a high-fat diet, the concentration of serum LDL-cholesterol was high (p<0.05), whereas the concentration of triglyceride was remarkably lower compared to other groups (p<0.05). The group fed 10% Erigeron annuus with a high-fat diet had the lowest concentration of blood phospholipids (p<0.05) as well as the highest alkaline phosphatase and alanine aminotransferase levels in blood (p<0.05). There was no difference in blood insulin concentration. However, blood leptin concentration was significantly higher (5.88±3.53 ng/dL) in mice fed a high-fat diet compared to other groups (p<0.05). Measurements of Erigeron annuus revealed that TPC, ABTS+ radical scavenging activity of trolox, DPPH radical scavenging activity, and the measured value of FRAP were higher in the ethanol extract than in the water extract. Especially, the antioxidant activity effects were excellent for the ABTS+ radical scavenging activities of trolox and FRAP values of Erigeron annuus. Therefore, Erigeron annuus powder showed antioxidant activity. Hence, Erigeron annuus powder drastically lessened triglyceride concentration in blood in high-fat diet-induced mice. Thus, the powder is considered to have utility in the food processing industry. Additional related experiments are ongoing.
        4,000원
        475.
        2015.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nanorod ZnO and spherical nano ZnO for gas sensors were prepared by hydrothermal reaction method and hydrazine method, respectively. The nano-ZnO gas sensors were fabricated by a screen printing method on alumina substrates. The gas sensing properties were investigated for hydrocarbon gas. The effects of Co concentration on the structural and morphological properties of the nano ZnO:Co were investigated by X-ray diffraction and scanning electron microscope (SEM), respectively. XRD patterns revealed that nanorod and spherical ZnO:Co with a wurtzite structure were grown with (1 0 0), (0 0 2), (1 0 1) peaks. The sensitivity of nanorod and spherical ZnO:Co sensors was measured for 5 ppm CH4 and CH3CH2CH3 gas at room temperature by comparing the resistance in air with that in target gases. The highest sensitivity to the CH4 and CH3CH2CH3 gas of spherical nano ZnO:Co sensors was observed at Co 6 wt%. The spherical nano ZnO:Co sensor exhibited a higher sensitivity to hydrocarbon gas than nanorod ZnO.
        4,000원
        476.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe-TiC composite powders are fabricated by planetary ball mill processing. Two kinds of powder mixtures are prepared from the starting materials of (a) (Fe, TiC) powders and (b) (Fe, TiH2, Carbon) powders. Milling speed (300, 500 and 700 rpm) and time (1, 2, and 3 h) are varied. For (Fe, TiH2, Carbon) powders, an in situ reaction synthesis of TiC after the planetary ball mill processing is added to obtain a homogeneous distribution of ultrafine TiC particulates in Fe matrix. Powder characteristics such as particle size, size distribution, shape, and mixing homogeneity are investigated. In case of (Fe, TiC) powder many coarse TiC particulates with size of several μm are unevenly distributed in Fe-matrix. The composite powder prepared from (Fe, TiH2, C) powder mixture showed a homogeneous dispersion of ulatrafine TiC particulates.
        4,000원
        477.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        SKD11 (ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. Adding of CNTs increased the performance of mechanical properties more. 1, 3 vol% CNTs was dispersed in SKD11 matrix by mechanical alloying. SKD11 carbon nanocomposite powder was sintered by spark plasma sintering process. FE-SEM, HR-TEM and Raman analysis were carried out for the SKD11 carbon nanocomposites.
        4,000원
        478.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Horse leg bone has been used as a traditional folk medicine for the sick and weak. Bone primarily contains collagen, a key building block of cells for bones, cartilage, and ligaments. In our previous study, horse leg bone hydrolysates showed anti-oxidation and skin protection effects against UV light. The aim of this study was to evaluate the quality of jelly containing Jeju crossbred horse leg bone hydrolysates at 0.3 (HLBH 0.3), 0.5 (HLBH 0.5) and 1.0% (HLBH 1.0). The HLBH 1.0 showed the highest pH and Brix values compare to control. Lightness (L*) and redness (a*) of HLBH 1.0 showed the lowest value compare to other treatments. However, yellowness (b*) of HLBH 0.3 and 0.5% was increased significantly with increasing levels of Jeju crossbred horse leg bone hydrolysates (p<0.05), while HLBH 0.5 and HLBH 1.0 showed no significant difference. Hardness and chewiness of jelly was decreased with increase of HLBH up to 0.5%, whereas no significant difference was found between HLBH 0.5 and 1.0. In sensory evaluation, panels did not tell the difference of jelly with different level of HLBH in all sensory factors likely color, appearance, flavor, chewiness, taste, and overall acceptability. This result suggests that Jeju crossbred horse leg bone hydrolysates can be used up to 1% without any significant bad influence on quality and sensory characteristics of jelly.
        4,000원
        479.
        2015.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        High temperature plasma coating technology has been applied to recover damaged aluminum dies from wear by spraying pure aluminum and alumina powder. However, the coated mixed powder layer composed of aluminum and alumina often undergoes a detachment from the substrate, making the coated substrate die unable to maintain its expected life span. In this study, in order to increase the bonding strength between the substrate and the coating layer, a pure aluminum layer was applied as an intermediate bond layer. In order to prepare the specimen with variable bond coating conditions, the bond coat layers with a various gun speed from 10 cm/sec to 30 cm/sec were prepared with coating cycle variations ranging from three to nine cycles. The specimen with a bond coat layer coated with a gun speed of 20 cm/sec and three coating cycles exhibited ~13MPa of adhesion strength, while the specimen without a bond coat layer showed ~6 MPa of adhesion strength. The adhesion strength with a variation of bond coat layer thickness is discussed in terms of coating parameters.
        4,000원