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        검색결과 2,185

        381.
        2016.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In order to reuse the photocatalyst and enhance the photolysis efficiency, we have used atmospheric pressure dielectric barrier discharge (APDBD) to clean and activate TiO2 powder. The photocatalytic activity of the TiO2 powder before and after APDBD treatment was evaluated by the degradation of methylene blue (MB) in aqueous solution. The apparent reaction rate constant of photolysis of the first sample of reused TiO2 cleaned by APDBD improved to a level up to 0.32h- 1 higher than the 30 % value of the initial TiO2 powder. As the number of photolysis reactions and APDBD cleanings increased, the apparent rate constants gradually decreased; however, the fourth photolysis reaction still showed a value that was greater than 10% of the initial value. In addition, APDBD treatment enhanced the process by which TiO2 effectively adsorbed MB at every photolysis stage.
        4,000원
        382.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The principal objective of this study was to evaluate the utilization of fish paste with added Capsosiphon fulvescens powder were 0, 3, 5, and 7%. The moisture, crude protein, crude lipid, crude ash and carbohydrate contents of the used Capsosiphon fulvescens powder were 8.5, 33.2% 1.1, 9.6, and 47.6%, respectively. For the Hunter color values, the L, a values of the fish paste decreased with increasing concentrations of Capsosiphon fulvescens powder. The b values of the fish paste appreciation with increasing concentrations of Capsosiphon fulvescens powder. And the folding test which represent the flexibility of the fish paste, all test samples showed AA. In the texture meter test, the hardness, strength, cohesiveness, and springiness increased according to increasing concentrations of Capsosiphon fulvescens powder. However, the gumminess and brittleness of the fish paste reduced by the addition of Capsosiphon fulvescens powder. In the sensory evaluation, color and taste of the fish paste were preferred 5% Capsosiphon fulvescens powder and the fish paste prepared with 5% Capsosiphon fulvescens powder were preferred over other fish pastes. These results suggest that Capsosiphon fulvescens powder can be applied to fish paste for the purpose of high quality and functionality.
        4,000원
        383.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tin is one of the most promising anode materials for next-generation lithium-ion batteries with a high energy density. However, the commercialization of tin-based anodes is still hindered due to the large volume change (over 260%) upon lithiation/delithiation cycling. To solve the problem, many efforts have been focused on enhancing structural stability of tin particles in electrodes. In this work, we synthesize tin nano-powders with an amorphous carbon layer on the surface and surroundings of the powder by electrical wire explosion in alcohol-based liquid media at room temperature. The morphology and microstructures of the powders are characterized by scanning electron microscopy, Xray diffraction, Raman spectroscopy, and transmission electron microscopy. The electrochemical properties of the powder for use as an anode material for lithium-ion battery are evaluated by cyclic voltammetry and a galvanometric dischargecharge method. It is shown that the carbon-coated tin nano-powders prepared in hexanol media exhibit a high initial charge specific capacity of 902 mAh/g and a high capacity retention of 89% after 50 cycles.
        4,000원
        384.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ni(OH)2 hollow spheres have been prepared by solvent displacement crystallization using a micro-injection device, and the effect of process parameters such as concentration and the relative ratio of the injection speed of the precursor solution, which is an aqueous solution of NiSO4·6H2O, to isopropyl alcohol of displacement solvent have been investigated. The crystal phases after NaOH treatment are in the β-phase for all process parameters. A higher concentration of NiSO4·6H2O aqueous solution is injected by a micro-injection device and bigger Ni(OH)2 hollow spheres with a narrower particle size distribution are formed. The crystallinity and hardness of the as-obtained powder are so poor that hydrothermal treatment of the as-obtained Ni(OH)2 at 120oC for 24 h in distilled water is performed in order to greatly improve the crystallinity. It is thought that a relative ratio of the injection speed of NiSO4·6H2O to that of isopropyl alcohol of at least more than 1 is preferable to synthesize Ni(OH)2 hollow spheres. It is confirmed that this solution- based process is very effective in synthesizing ceramic hollow spheres by simple adjustment of the process parameters such as the concentration and the injection speed.
        4,000원
        385.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        TiOF2, which has remarkable electrochemical and optical properties, is used in various applications such as Li-ion batteries, electrochemical displays, and photocatalysts. In addition, it is possible to utilize the template which is allowed to synthesize fluorine doped TiO2 powders with hollow or faceted structures. However, common synthesis methods of TiOF2 powders have some disadvantages such as the use of expensive and harmful precursors and batchtype processes with a limited production scale. In this study, we report a synthetic route for preparing TiOF2 powders by using an inexpensive and harmless precursor and a continuous ultrasonic spray pyrolysis process under a controlled atmosphere to address the aforementioned problems. The synthesized powder has an average size of 1 μm, a spherical shape, a pure TiOF2 phase, and exhibits a band-gap energy of 3.2 eV.
        3,000원
        386.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An optimum route to synthesize Ti-Mo system powders is investigated by analyzing the effect of the heat treatment atmosphere on the formation of the reaction phase by dehydrogenation and hydrogen reduction of ball-milled TiH2-MoO3 powder mixtures. Homogeneous powder mixtures with refined particles are prepared by ball milling for 24 h. XRD analysis of the heat-treated powder in a hydrogen atmosphere shows TiH2 and MoO3 peaks in the initial powders as well as the peaks corresponding to the reaction phase species, such as TiH0.7, TiO, MoO2, Mo. In contrast, powder mixtures heated in an argon atmosphere are composed of Ti, TiO, Mo and MoO3 phases. The formation of reaction phases dependent on the atmosphere is explained by the partial pressure of H2 and the reaction temperature, based on thermodynamic considerations for the dehydrogenation reaction of TiH2 and the reduction behavior of MoO3.
        3,000원
        387.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ni1/3Co1/3Mn1/3(OH)2 powders have been synthesized in a continuously stirred tank reactor via a co-precipitation reaction between aqueous metal sulfates and NaOH using NH4OH as a chelating agent. The co-precipitation temperature is varied in the range of 30-80oC. Calcination of the prepared precursors with Li2CO3 for 8 h at 1000oC in air results in Li Ni1/3Co1/3Mn1/3O2 powders. Two kinds of obtained powders have been characterized by X-ray diffraction (XRD), scanning electron microscopy, particle size analyzer, and tap density measurements. The co-precipitation temperature does not differentiate the XRD patterns of precursors as well as their final powders. Precursor powders are spherical and dense, consisting of numerous acicular or flaky primary particles. The precursors obtained at 70 and 80oC possess bigger primary particles having more irregular shapes than those at lower temperatures. This is related to the lower tap density measured for the former. The final powders show a similar tendency in terms of primary particle shape and tap density. Electrochemical characterization shows that the initial charge/discharge capacities and cycle life of final powders from the precursors obtained at 70 and 80oC are inferior to those at 50oC. It is concluded that the optimum co-precipitation temperature is around 50oC.
        4,000원
        388.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Graphene oxide (GO) powder processed by Hummer's method is mixed with p-type Bi2Te3 based thermoelectric materials by a high-energy ball milling process. The synthesized GO-dispersed p-type Bi2Te3 composite powder has a composition of Bi0.5Sb1.5Te3 (BSbT), and the powder is consolidated into composites with different contents of GO powder by using the spark plasma sintering (SPS) process. It is found that the addition of GO powder significantly decreases the thermal conductivity of the pure BSbT material through active phonon scattering at the newly formed interfaces. In addition, the electrical properties of the GO/BSbT composites are degraded by the addition of GO powder except in the case of the 0.1 wt% GO/BSbT composite. It is found that defects on the surface of GO powder hinder the electrical transport properties. As a result, the maximum thermoelectric performance (ZT value of 0.91) is achieved from the 0.1% GO/BSbT composite at 398 K. These results indicate that introducing GO powder into thermoelectric materials is a promising method to achieve enhanced thermoelectric performance due to the reduction in thermal conductivity.
        4,000원
        389.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Muffin was developed using blueberry powder and the shelf life of the muffin packaged in modified atmosphere was determined. Blueberry was freeze-dried and milled to prepare powder. As the concentration of blueberry powder increased from 0 to 15% (w/w), hardness and gumminess also increased (p<0.05). The Hunter L and b values of the crust and crumb of muffin decreased as the concentration increased, while their Hunter a values increased. Blueberry powder concentrations of 10 and 15% resulted in high preference in taste, texture, and overall acceptability. Blueberry muffin containing powder at 10% was packaged in modified atmosphere (MA). The optimum gas for modified atmosphere packaging (MAP) of the muffin was the mixture of carbon dioxide (CO2) and nitrogen (N2) (7:3), which improved microbial stability without altering muffin hardness. The shelf life of modified atmosphere packaged blueberry muffin was determined using the accelerated life test. The shelf life values for MA packaged blueberry muffin stored at 25 and 35°C were predicted as 21 and 5 d, respectively. Further, the Q10 values for 25- 35°C and 35-45°C were determined as 4.2 and 2.9, respectively. The MAP can preserve blueberry muffin for 3 weeks at 25°C, without the external addition of preservatives.
        4,000원
        390.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnetostrictive actuator is fabricated with powder nano bonding method instead of sputtering method. Fabrication process and experimental measurement method for magneto-mechanical characteristics is proposed. For the design of highly flexible magnetostrictive actuator, TbDyFe nano powder bonding with Teflon substrate is adopted. The fabrication process for Teflon substrate and nano powder bonding is suggested and magnetostrictive behaviors are investigated. Variable magnetic field is applied to measure the magnetostrictive characteristics and magnetostriction is measured with different waves and different magnitude of magnetic field.
        4,000원
        391.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, solid solution heat treatment of consolidated nickel-based superalloy powders is carried out by hot isotactic pressing. The effects of the cooling rate of salt quenching, and air cooling on the microstructures and the mechanical properties of the specimens are analyzed . The specimen that is air cooled shows the formation of serrated grain boundaries due to their obstruction by the carbide particles. Moreover, the specimen that is salt quenched shows higher strength than the one that is air cooled due to the presence of fine and close-packed tertiary gamma prime phase. The tensile elongation at high temperatures improves due to the presence of grain boundary serrations in the specimen that is air cooled. On the contrary, the specimen that is salt quenched and consists of unserrated grain boundaries shows better creep properties than the air cooled specimen with the serrated grain boundaries, due to the negative creep phenomenon.
        4,000원
        392.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the effects of Capsosiphon fulvescens powder on the functional and sensory characteristics of dumpling shell. Various dumpling shell samples were prepared with wheat flour along with the addition of different amounts of Capsosiphon fulvescens powder, and then instrumental characteristics and sensory evaluations were investigated. According to amylograph data, the composite Capsosiphon fulvescens powder-wheat flour samples had increased gelatinization temperatures with increasing Capsosiphon fulvescens powder content; whereas initial viscosity at 95oC, viscosity at 95oC after 15minutes, and maximum viscosity were reduced. In terms of Hunter's color values, L, a and b values decreased with increasing Capsosiphon fulvescens powder content. Besides cooked weight, cooked volume and turbidity of dumpling shell increased as the addition level of Capsosiphon fulvescens powder increase. In terms of textural characteristics, addition of Capsosiphon fulvescens powder increased springiness, chewiness, brittleness, pringiness and adhesiveness. Based on sensory evaluations, the overall preference of dumpling shell with 3% added Capsosiphon fulvescens powder, was more effective than control.
        4,000원
        393.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Copper nanoparticles attract much attention as substitutes of noble metals such as silver and can help reduce the manufacturing cost of electronic products due to their lower cost and good conductivity. In the present work, the chemical reduction is examined to optimize the synthesis of nano-sized copper particles from copper sulfate. Sodium borohydride and ascorbic acid are used as reducing and antioxidant agents, respectively. Polyethylene glycol (PEG) is used as a size-control and capping agent. An appropriate dose of PEG inhibits the abnormal growth of copper nanoparticles, maintaining chemical stability. The addition of ascorbic acid prevents the oxidation of nanoparticles during synthesis and storage. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) are used to investigate the size of the synthesized nanoparticles and the coordination between copper nanoparticles and PEG. For chemical reduction, copper nanoparticles less than 100 nm in size without oxidized layers are successfully obtained by the present method.
        4,000원
        394.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study Muffins adding each 0, 1, 3, 5 7% of Acai Berry powder, which has very high anti-oxidant constituent, have been made, and its quality characteristics have been surveyed. From the volume and specific volume measurement, it has been decreased for MA1, 1% of Acai Berry powder added muffin, but the tendency thereafter has shown increasing (p<0.001). From texture characteristics gumminess and chewiness of MA0, reference group, was the highest by 885.86 g/ cm and 6645.71 g, and has shown decreasing tendency as per the adding rate of Acai Berry powder increased (0.001). The electronics scavenging activity of MA7, 7% added muffin, was the highest by 68.91%, and the ascending order was MA1 < Reference Group < MA3 < MA5 < MA7. From the preference test of Acai Berry powder added muffin, MA3, 3% added muffin, was the most preferable one from color, taste as well as total preference. As the added volume of Acai Berry powder is 5% or more, the typical taste and flavor of Acai Berry gives influence to the taste and flavor of muffin, so the preference level has been decreased. Thus the added volume of Acai Berry powder 5% or more is not recommendable.
        4,000원
        395.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Waste oyster shells create several serious problems; however, only some parts of them are being utilized currently. The ideal solution would be to convert the waste shells into a product that is both environmentally beneficial and economically viable. An experimental study is carried out to investigate the recycling possibilities for oyster shell waste. Bulk ceramic bodies are produced from the oyster shell powder in three sequential processes. First, the shell powder is calcined to form calcium oxide CaO, which is then slaked by a slaking reaction with water to produce calcium hydroxide Ca(OH)2. Then, calcium hydroxide powder is formed by uniaxial pressing. Finally, the calcium hydroxide compact is reconverted to calcium carbonate via a carbonation reaction with carbon dioxide released from the shell powder bed during firing at 550oC. The bulk body obtained from waste oyster shells could be utilized as a marine structural porous material.
        4,000원
        396.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated properties of bread utilizing extracts of ginseng powder. Ginseng powder bread was baked. Addition of 1~3% of ginseng powder extract to wheat flour was carried out. Rheological properties, dough pH, dough volume, bread volume, water absorption capacity, baking loss, bread color, bread texture, and sensory evaluation were tested to examine properties of bread baked with extracts of ginseng powder. The results are as follows. The dough pH decreased gradually with increasing ginseng powder extract concentration. The bread volume, baking loss, and bread weight increased with increasing use of ginseng powder extract, and springiness and cohesiveness increased as red ginseng powder additive concentration increased. Lightness of the L decreased while a and b increased. In the sensory evaluation, ginseng powder with 1% ginseng powder extract was evaluated as the best for taste, texture, flavor, and overall acceptability.
        4,000원
        397.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to evaluate physicochemical properties of model sausages with various levels of pressed cherry fruit extracts alone or in combination with tomato powders as a partial replacement of sodium nitrite. In study 1, physicochemical properties of model sausages were not affected by the addition of pressed cherry fruit extracts(p>0.05), except for Hunter L(lightness) and Hunter a(redness). Model sausages containing pressed cherry fruit extract(T1, 0.5% and T2, 1.0%) decreased lightness, whereas redness of REF(156 ppm sodium nitrite) was not different from T2(p>0.05). However, those with cherry fruit extract at 1% were proper to improve the hunter color values, especially redness values. In study 2, physicochemical properties of model sausages were not affected by the addition of pressed cherry fruit extract and tomato powders in selected nitrite contents, except for color and cooking loss(p>0.05). In color values, REF was the highest level, and T2, T4, and T5 was significantly low level in lightness (Hunter L). T2 was the highest value in cooking loss(%) among other treatments. The redness values(Hunter a) of T5(75ppm, nitrite, 1% pressed cherry fruit extract and 0.5% tomato powder) were not different from REF which had highest redness values(P<0.05). In conclusion, the combination of pressed cherry fruit and tomato powder might be considered as an alternative method to partially replace with sodium nitrite in pork model sausages.
        4,000원
        398.
        2016.06 구독 인증기관 무료, 개인회원 유료
        투명한 교류 분말형 전계발광 소자는 Electroluminescence (EL) 용 ZnS계 형광체와 시아노 에틸 유기바인더의 첨가량을 달리하여 제작하였다. 전면전극 indium thin oxide(ITO) glass 위에 약 3 μm 크기 의 형광체로 발광층을 형성하여 silver nanowire(Ag NW)를 스핀코팅으로 후면전극 형성 후 연구를 진행 하였다. 본 연구에 제작된 소자의 발광휘도와 투과도을 통해 등황색 계열의 약 585 nm의 주파장 스펙트 럼을 확인하였고 형광체의 첨가량이 낮아질수록 발광휘도가 약 80 %로 감소, 투과도는 약 30 % 증가하 는 것을 알 수 있었다.
        4,000원
        399.
        2016.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cu-30 vol% SiC composites with relatively densified microstructure and a sound interface between the Cu and SiC phases were obtained by pressureless sintering of PCS-coated SiC and Cu powders. The coated SiC powders were prepared by thermal curing and pyrolysis of PCS. Thermal curing at 200 oC was performed to fabricate infusible materials prior to pyrolysis. The cured powders were heated treated up to 1600 oC for the pyrolysis process and for the formation of SiC crystals on the surface of the SiC powders. XRD analysis revealed that the main peaks corresponded to the α-SiC phase; peaks for β-SiC were newly appeared. The formation of β-SiC is explained by the transformation of thermally-cured PCS on the surface of the initial α-SiC powders. Using powder mixtures of coated SiC powder, hydrogen-reduced Cu-nitrate, and elemental Cu powders, Cu-SiC composites were fabricated by pressureless sintering at 1000 oC. Microstructural observation for the sintered composites showed that the powder mixture of PCS-coated SiC and Cu exhibited a relatively dense and homogeneous microstructure. Conversely, large pores and separated interfaces between Cu and SiC were observed in the sintered composite using uncoated SiC powders. These results suggest that Cu-SiC composites with sound microstructure can be prepared using a PCS coated SiC powder mixture.
        4,000원
        400.
        2016.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, an environment-friendly synthetic strategy to process zinc oxide nanocrystals is reported. The biosynthesis method used in this study is simple and cost-effective, with reduced solvent waste via the use of fruit peel extract as a natural ligation agent. The formation of ZnO nanocrystals using a rambutan peel extract was observed in this study. Rambutan peels has the ability to ligate zinc ions as a natural ligation agent, resulting in ZnO nanochain formation due to the presence of an extended polyphenolic system over the whole incubation period. Via transmission electron microscopy, successful formation of zinc oxide nanochains was confirmed. TEM observation revealed that the bioinspired ZnO nanocrystals were spherical and/or hexagonal particles with sizes between 50 and 100 nm.
        4,000원